Method and apparatus for pusch/pucch power scaling considering dual connectivity in power limited state

ABSTRACT

Provided is a method and apparatus for executing an uplink channel power control in dual connectivity configuration when power is limited. An appropriate power controlling method may be determined based on a priority, and may be applied to a UE that has dual connectivity with a Master eNB (MeNB) and a Secondary eNB (SeNB) in a network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 15/174,689, filed on Jun. 6, 2016, which is acontinuation of and claims priority to U.S. patent application Ser. No.14/664,746, filed on Mar. 20, 2015 (now U.S. Pat. No. 9,386,532 issuedJul. 5, 2016), and claims priority to and the benefit of Korean PatentApplication No. 10-2014-0033276, filed on Mar. 21, 2014, each of whichis hereby incorporated by reference in its entirety.

BACKGROUND

1. Field

Exemplary embodiments relate to wireless communication, and moreparticularly, to a method and apparatus for executing PUSCH/PUCCH powercontrol and/or power scaling in a power-limited state.

2. Description

In a wireless communication system, a User Equipment (UE) may executewireless communication through two or more evolved NodeBs (eNB) fromamong eNBs forming at least one serving cell. This is an example ofconfiguring dual connectivity with at least two nodes. In other words,the dual connectivity refers to an operation in which a UE that is in aRadio Resource Control (RRC) connected state with two or more differentnetwork points, consumes radio resources provided by the network points.Here, the at least two different network points may be a plurality ofeNBs that are physically or logically distinguished from one another.One of them may be a Master eNB (MeNB) and the remaining eNBs may beSecondary eNBs (SeNB).

In the dual connectivity, each eNB transmits downlink data and receivesuplink data, through a bearer configured for a UE. In this instance, abearer may be configured through a single eNB, or two or more differenteNBs. In addition, in the case of dual connectivity, at least oneserving cell may be configured for each eNB, and each serving cell mayoperate in an activated or deactivated state. In this instance, aPrimary (serving) Cell that may be configurable based on an existingComponent Carrier Aggregation (CA), may be configured for the MeNB.Here, the CA is to effectively use small band segments, which binds aplurality of physically continuous or non-continuous bands in afrequency domain so as to provide an effect same as when an eNB uses alogically large band.

For a SeNB, only a Secondary (serving) Cell (SCell) may be configured.In at least one of the SCells of SeNBs, a Physical Uplink ControlCHannel (PUCCH) which is a physical channel for transmitting uplinkcontrol information may be configured. A serving cell group that isprovided by the MeNB is referred to as a Master Cell Group (MCG), and aserving cell group that is provided by the SeNB is referred to as aSecondary Cell Group (SCG).

An eNB may use power headroom information of a UE to effectively utilizeresources of the UE. Power control technology is an essential technologyfor minimizing interference elements for effective distribution ofresources in wireless communication and for reducing battery powerconsumption. When a UE provides power headroom information to an eNB,the eNB may estimate an uplink maximum transmission power {circumflexover (P)}_(CMAX)(i) that may be allocated to the UE. Therefore, the eNBmay provide the UE with uplink scheduling such as Transmit Power Control(TPC), Modulation and Coding Scheme (MCS), a bandwidth, or the like,within the range of the estimated uplink maximum transmission power.

Unlike the assumption in the existing Long Term Evolution (LTE) system,when dual connectivity is configured for a UE, the UE may connect to atleast two eNBs having independent schedulers, and transmit and receivedata. Therefore, there is a desire for a new transmission power controlmethod for a UE due to a difference in physical channel propertiesbetween a UE and a plurality of eNBs that the UE connects to (forexample, a pathloss), a different Quality of Service (QoS), a dualconnectivity mode (for example, 1A/3C), independent schedulers of theplurality of eNBs, or the like. Particularly, power of a UE in dualconnectivity may be limited (for example, a total transmit power of a UEmay exceed {circumflex over (P)}_(CMAX)(i)). Under the above situation,there is a desire for a power scaling scheme for a UE to execute uplinktransmission to a plurality of eNBs through a plurality of uplinkchannels in a single subframe.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the inventive conceptand therefore it may contain information that does not form any part ofthe prior art nor what the prior art may suggest to a person of ordinaryskill in the art.

SUMMARY

One or more exemplary embodiments provide a method and apparatus forcontrolling a transmit power reduction of an uplink channel based on apriority determination between two or more uplink channels.

Additional aspects will be set forth in the detailed description whichfollows, and, in part, will be apparent from the disclosure, or may belearned by practice of the inventive concept.

One or more exemplary embodiments provide a Physical Uplink SharedCHannel (PUSCH) power control method and an apparatus thereof, whenpower is limited, while configuring dual connectivity with at least twoeNodeBs.

One or more exemplary embodiments provide a PUCCH power control methodand an apparatus thereof, when power is limited.

One or more exemplary embodiments provide a PUSCH power scaling methodand an apparatus thereof, for a User Equipment (UE) for which dualconnectivity is configured.

One or more exemplary embodiments provide a PUCCH power scaling methodand an apparatus thereof, for a UE for which dual connectivity isconfigured.

According to one or more exemplary embodiments, a UE may variously set adegree of power scaling based on a determination whether a PUSCH istransmitted through a cell in a MCG or a cell in an SCG.

According to one or more exemplary embodiments, a UE may variously set adegree of power scaling based on a determination whether a PUSCH and aPUCCH are simultaneously transmitted.

According to one or more exemplary embodiments, a UE may variously set adegree of power scaling based on a determination whether a PUSCH carriesUplink Control Information (UCI).

One or more exemplary embodiments provide a method of controlling atransmit power by a User Equipment (UE), the UE being capable ofconfiguring dual connectivity, the method including: establishing aRadio Resource Control (RRC) connection with a Master evolved NodeB(MeNB) through a primary serving cell, the MeNB being associated with aMaster Cell Group (MCG) including one or more serving cells configurablefor the UE; establishing a connection with a Secondary eNB (SeNB), theSeNB being associated with a Secondary Cell Group (SCG) including one ormore serving cells configurable for the UE; determining to transmit anuplink channel through a serving cell of the MCG and to transmit anuplink channel through a serving cell of the SCG; determining whether tocontrol a transmit power reduction for at least one of the uplinkchannel determined to be transmitted through the serving cell of the MCGand the uplink channel determined to be transmitted through the servingcell of the SCG; determining a priority between the uplink channeldetermined to be transmitted through the serving cell of the MCG and theuplink channel determined to be transmitted through the serving cell ofthe SCG, based on Uplink Control Information (UCI) included in at leastone of the uplink channels and based on a type of a cell group;controlling the transmit power reduction for a lower-prioritized uplinkchannel from among the uplink channels; and transmitting, from the UE,the uplink channels through the respective serving cells after thecontrol of the transmit power reduction.

One or more exemplary embodiments provide a method of controlling atransmit power by a User Equipment (UE), the UE being capable ofconfiguring dual connectivity, the method including: establishing aRadio Resource Control (RRC) connection with a Master evolved NodeB(MeNB) through a primary serving cell, the MeNB being associated with aMaster Cell Group (MCG) including one or more serving cells configurablefor the UE; establishing a connection with a Secondary eNB (SeNB), theSeNB being associated with a Secondary Cell Group (SCG) including one ormore serving cells configurable for the UE; determining to transmit anuplink channel through a first serving cell of the SCG and to transmitan uplink channel through a second serving cell of the SCG; determiningwhether to control a transmit power reduction for at least one of theuplink channel determined to be transmitted through the first servingcell of the SCG and the uplink channel determined to be transmittedthrough the second serving cell of the SCG; determining a prioritybetween the uplink channel determined to be transmitted through theserving cell of the MCG and the uplink channel determined to betransmitted through the serving cell of the SCG, based on adetermination whether Uplink Control Information (UCI) is included in atleast one of the uplink channels and a determination of a UCIcharacteristic; controlling the transmit power reduction for alower-prioritized uplink channel from among the uplink channels; andtransmitting, from the UE, the uplink channels through the respectiveserving cells after the control of the transmit power reduction.

One or more exemplary embodiments provide a method of controlling atransmit power by a User Equipment (UE), the UE being capable ofconfiguring dual connectivity, the method including: establishing aRadio Resource Control (RRC) connection through a primary serving cellincluded in a Master Cell Group (MCG), the MCG being associated with aMaster evolved NodeB (MeNB) providing one or more serving cellsconfigurable for the UE; configuring, for the UE, a serving cellincluded in a Secondary Cell Group (SCG), the SCG being associated witha Secondary eNB (SeNB) providing one or more secondary serving cellsconfigurable for the UE; determining to transmit uplink channels, insubframe through two or more serving cells selected from at least one ofthe MCG and the SCG; determining whether to control a transmit powerreduction for at least one of the uplink channels; determining apriority between the uplink channels, based on a determination whetherUplink Control Information (UCI) is included in at least one of theuplink channels and a determination of a UCI characteristic; controllingthe transmit power reduction for a lower-prioritized uplink channel fromamong the uplink channels; and transmitting, from the UE, the uplinkchannels through the respective serving cells after the control of thetransmit power reduction.

According to one or more exemplary embodiments, a PUSCH/PUCCHtransmission power may be effectively controlled with respect to a UserEquipment (UE) having dual connectivity with a Master eNB (MeNB) and aSecondary eNB (SeNB) in a network, and, based on the same, theperformance of uplink scheduling may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a network architecture of a wirelesscommunication system, according to one or more exemplary embodiments.

FIG. 2 is a block diagram illustrating a radio protocol architectureassociated with a user plane, according to one or more exemplaryembodiments.

FIG. 3 is a block diagram illustrating a radio protocol architectureassociated with a control plane, according to one or more exemplaryembodiments.

FIG. 4 is a diagram illustrating the architecture of a bearer service ina wireless communication system, according to one or more exemplaryembodiments.

FIG. 5 is a diagram illustrating an example of a dual connectivitysituation of a User Equipment (UE), according to one or more exemplaryembodiments.

FIG. 6 is a diagram illustrating the architecture of a user plane fordual connectivity, according to one or more exemplary embodiments.

FIG. 7 and FIG. 8 are diagrams illustrating examples of a protocolarchitecture of evolved NodeBs (eNBs) during downlink transmission ofuser plane data in dual connectivity, according to one or more exemplaryembodiments.

FIG. 9 is a diagram illustrating an example of a Media Access Control(MAC) entity architecture corresponding to the protocol architecture ofFIG. 7 and FIG. 8, according to one or more exemplary embodiments.

FIG. 10 is a diagram illustrating another example of a MAC entityarchitecture corresponding to the protocol architecture of FIG. 7 andFIG. 8, according to one or more exemplary embodiments.

FIGS. 11A and 11B show two diagrams illustrating examples of non-equalpower scaling between cell groups for Case 1, according to one or moreexemplary embodiments.

FIG. 12 is a diagram illustrating an example of power scaling withrespect to a PUSCH with Uplink Control Information (UCI) and a PUSCHwithout UCI for Case 2, according to one or more exemplary embodiments.

FIG. 13 is a diagram illustrating another example of power scaling withrespect to a PUSCH with UCI and a PUSCH without UCI for Case 2,according to one or more exemplary embodiments.

FIG. 14 is a diagram illustrating an example of power scaling withrespect to a PUSCH with UCI and a PUSCH without UCI for Case 3,according to one or more exemplary embodiments.

FIG. 15 is a diagram illustrating another example of power scaling withrespect to a PUSCH with UCI and a PUSCH without UCI for Case 2,according to one or more exemplary embodiments.

FIG. 16 is an example of a flowchart illustrating an uplink powercontrolling operation executed by a UE, according to one or moreexemplary embodiments.

FIG. 17 is an example of a block diagram illustrating a UE, according toone or more exemplary embodiments.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Hereinafter, exemplary embodiments will be described with reference tothe accompanying drawings. In the following description, the sameelements will be designated by the same reference numerals although theyare shown in different drawings. Further, in the following description,a detailed description of known functions and configurationsincorporated herein will be omitted when it may make the subject matterof exemplary embodiments rather unclear.

In addition, the present specification provides descriptions inassociation with a wireless communication network, and tasks executed inthe wireless communication network may be performed in the process wherea system (for example, a base station) that manages the correspondingwireless communication network controls a network and transmits data, ormay be performed in a terminal that connects to the correspondingwireless network.

FIG. 1 is a diagram illustrating a network architecture of a wirelesscommunication system, according to one or more exemplary embodiments.

FIG. 1 illustrates the network architecture of an Evolved-UniversalMobile Telecommunications System (E-UMTS), which is an example of awireless communication system. The E-UMTS system may be Evolved-UMTSTerrestrial Radio Access (E-UTRA), Long Term Evolution (LTE), orLTE-advanced (LTE-A). The wireless communication system may utilizevaried multiple access schemes, such as CDMA (Code Division MultipleAccess), TDMA (Time Division Multiple Access), FDMA (Frequency DivisionMultiple Access), OFDMA (Orthogonal Frequency Division Multiple Access),Single Carrier-FDMA (SC-FDMA), OFDM-FDMA, OFDM-TDMA, OFDM-CDMA, and thelike.

Referring to FIG. 1, an Evolved-UMTS Terrestrial Radio Access Network(E-UTRAN) includes a base station (hereinafter referred to as an evolvedNodeB (eNB) 20) that provides a terminal (hereinafter referred to asUser Equipment (UE) 10) with a Control Plane (CP) and a User Plane (UP).

The UE 10 may be a stationary or mobile entity, and may be referred toas a Mobile station (MS), an Advanced MS (AMS), a User Terminal (UT), aSubscriber Station (SS), a wireless device, or the like.

The eNB 20 may generally refer to a station that communicates with theUE 10, and may be referred to as a Base Station (BS), a Base TransceiverSystem (BTS), an access point, a femto-eNB, a pico-eNB, a Home eNB, arelay, or the like. The eNBs 20 may be physically connected to oneanother through an optical cable or a Digital Subscriber Line (DSL), orthe like, and may exchange signals or messages through an X2 or Xninterface. FIG. 1 exemplifies the case in which eNBs 20 are connected toone another through an X2 interface.

Hereinafter, descriptions associated with a physical connection will beomitted and a logical connection will be described. As illustrated inFIG. 1, the eNB 20 is connected to an Evolved Packet Core (EPC) 30through an S1 interface. In particular, the eNB 20 is connected to aMobility Management Entity (MME) through an S1MME interface, and isconnected to a Service Gateway (S-GW) through an S1-U interface. The eNB20 may exchange context information of the UE 10 and information forsupporting mobility of the UE 10, with the MME through the S1-MMEinterface. In addition, the eNB 20 may exchange data to be provided toeach UE 10, with an S-GW through the S1-U interface.

Although not illustrated in FIG. 1, the EPC 30 includes an MME, an S-GW,and a Packet data network-Gateway (P-GW). The MME has access informationof the UE 10 or information associated with capability of the UE 10, andthe information may be used for mobility management of the UE 10. TheS-GW is a gateway having an E-UTRAN as an end point, and the P-GW is agateway having a Packet Data Network (PDN) as an end point.

The E-UTRAN and the EPC 30 together are referred to as an Evolved PacketSystem (EPS), and a traffic flow from a radio link through which the UE10 accesses the eNB 20 to a PDN that provides a connection to a serviceentity, may be operated based on an Internet Protocol (IP).

A radio interface between the UE 10 and the eNB 20 is referred to as a“Uu interface.” The layers of a Radio Interface Protocol between the UE10 and a network are classified into a first layer (L1), a second layer(L2), and a third layer (L3), which are defined by 3rd GenerationPartnership Project (3GPP)-affiliated wireless communication system,such as, UMTS, LTE, LTE-Advanced, or the like. A physical layer belongsto the first layer among them, provides information transfer servicesusing a physical channel, and a Radio Resource Control (RRC) layerlocated in the third layer provides radio resources between the UE 10and the network by exchanging an RRC message.

FIG. 2 is a block diagram illustrating a radio protocol architectureassociated with a user plane, according to one or more exemplaryembodiments. FIG. 3 is a block diagram illustrating a radio protocolarchitecture associated with a control plane, according to one or moreexemplary embodiments. The user plane indicates a protocol stack foruser data transmission, and the control plane indicates a protocol stackfor control signal transmission.

Referring to FIGS. 2 and 3, each Physical (PHY) layer of a UE and an eNBprovides an information transfer service to a higher layer using aphysical channel. The physical layer is connected to a Media AccessControl layer which is a higher layer, through a transport cannel. Datais transferred through a transport channel between the MAC layer and thephysical layer. The transport channel is classified based on a scheme oftransmitting data through a radio interface. In addition, data istransferred through a physical channel between different physical layers(that is, between physical layers of a UE and an eNB). The physicalchannel may be modulated based on an Orthogonal Frequency DivisionMultiplexing (OFDM) scheme, and uses a space formed of time andfrequencies, and a space formed of a plurality of antennas as radioresources.

For example, a Physical Downlink Control CHannel (PDCCH) among physicalchannels may inform a UE of resource allocation of a Paging CHannel(PCH) and a DownLink Shared CHannel (DL-SCH) and Hybrid Automatic RepeatRequest (HARQ) information associated with a DL-SCH, and may deliver, toa UE, uplink scheduling grant which reports resource allocation ofuplink transmission. A Physical Control Format Indicator CHannel(PCFICH) informs a UE of the number of OFDM symbols used for PDCCHs, andis transmitted for each subframe. A Physical Hybrid ARQ IndicatorCHannel (PHICH) carries a HARQ ACK/NACK signal as a response to uplinktransmission. In addition, a Physical Uplink Control CHannel (PUCCH)delivers HARQ ACK/NACK with respect to downlink transmission and uplinkcontrol information such as a scheduling request and a Channel QualityIndicator (CQI). A Physical Uplink Shared CHannel (PUSCH) delivers anUpLink Shared CHannel (UL-SCH). The PUSCH may include HARQ ACK/NACK andChannel State Information (CSI) such as a CQI.

The MAC layer may execute mapping between a logical channel and atransport channel, and execute multiplexing or demultiplexing between atransport channel of a MAC Service Data Unit (SDU) that belongs to thelogical channel and a transport block provided in a physical channel.The MAC layer provides services to a Radio Link Control (RLC) layerthrough the logical channel. The logical channel is classified into acontrol channel for transferring control area information and a trafficchannel for transferring user area information. For example, servicesprovided from the MAC layer to a higher layer include data transmissionor radio resource allocation.

The functions of the RLC layer include concatenation, segmentation, andreassembly of an RLC SDU. The RLC layer provides three types ofoperation modes, such as, a Transparent Mode (TM), an UnacknowledgedMode (UM) and an Acknowledged Mode (AM), to secure various Quality ofServices (QoS) required by a Radio Bearer (RB).

Generally, the TM is used for setting an initial connection. The UM isfor real time data transmission such as data streaming or a Voice overInternet Protocol (VoIP), which places importance on speed rather thanthe reliability of data. However, the AM is a mode that placesimportance on the reliability of data rather than speed, and isappropriate for high capacity data transmission or data transmissionwhich is less sensitive to transmission delay. An eNB determines themode of an RLC in an RB corresponding to each EPS bearer, based on QoSinformation of a corresponding EPS bearer that has a connection with aUE, and configures parameters in an RLC to satisfy QoS.

RLC SDUs are provided in various sizes, and for example, may be providedbased on a byte unit. RLC Protocol Data Units (PDUs) may be defined onlywhen a transmission opportunity is reported from a lower layer (forexample, a MAC layer), and is transferred to a lower layer. Thetransmission opportunity may be reported together with the total size ofRLC PDUs to be transmitted. Alternatively, the transmission opportunityand the total size of RLC PDUs to be transmitted may be separatelyreported.

The function of a Packet Data Convergence Protocol (PDCP) layer in theuser plane includes user data transmission, header compression, andciphering, and control plane data transmission and ciphering/integrityprotection.

Referring to FIG. 3, a RRC layer controls a logical channel, a transportchannel, and a physical channel, in association with configuration,reconfiguration, and release of RBs. An RB indicates a logical pathprovided by a first layer (PHY layer) and a second layer (MAC layer, RLClayer, and PDCP layer), for transferring data between a UE and anetwork. A process of configuring an RB indicates a process that definesproperties of radio protocol layer and a channel for providing apredetermined service, and sets corresponding detailed parameters and anoperation method. An RB may be classified into a Signaling RB (SRB) anda Data RB (DRB). The SRB is used as a path for transmitting an RRCmessage and a Non-Access Stratum (NAS) message in the control plane, andthe DRB is used as a path for transmitting user data in the user plane.

A Non-Access Stratum (NAS) layer located in the upper portion of the RRClayer executes functions such as session management, mobilitymanagement, and the like. When an RRC connection exists between the RRClayer of a UE and the RRC layer of an E-UTRAN, the UE is in an RRCconnected state, and otherwise, the UE is in an RRC idle state.

Resources need to be allocated to various paths among mobilecommunication network entities existing between a UE and an externalInternet network, to enable the UE to transmit user data (for example,an IP packet) to the external network or to receive user data from theexternal network. As described above, a path that is capable ofexecuting data transmission and reception through resources allocatedbetween mobile communication network entities, is referred to as abearer.

FIG. 4 is a diagram illustrating a structure of a bearer service in awireless communication system, according to one or more exemplaryembodiments.

In FIG. 4, a path for providing an End-to-End service between a UE andan internet network is illustrated. Here, the End-to-End service refersto a service that requires a path between a UE and a P-GW (an EPSbearer) and a path between the P-GW and the external internet network(an external bearer) for a data service between the UE and the internetnetwork. The external path may be the bearer between the P-GW and theinternet network.

In order to transmit data from a UE to an external internet network, theUE transmits data to a base station (eNB) via an RB. Then, the basestation transmits the data received from the UE to an S-GW via an S1bearer. The S-GW transmits the data received from the base station to aP-GW via an S5/S8 bearer, and the P-GW transmits the data received fromthe S-GW to a destination in the external internet network via theexternal bearer.

Likewise, in order to transmit data from the external internet networkto the UE, the data may be transmitted via the above mentioned bearersaccording to the reverse direction of the data transmission directionfrom the UE to the external internet network described above.

As described above, different bearers may be defined for each interfacein a wireless communication system, thereby ensuring independencebetween interfaces. Hereinafter, bearers of each interface will bedescribed in more detail.

The bearers provided by a wireless communication system may be referredto as an EPS bearer. The EPS bearer may be a path configured between aUE and a P-GW for transmitting an IP traffic with a specific QoS. TheP-GW may receive an IP flow from an internet network or transmit an IPflow to the internet network. Each EPS bearer may be configured by QoSdetermination parameters, which indicate a characteristic of a transportpath. One or more EPS bearers may be configured for a UE, and one EPSbearer may indicate one E-UTRAN Radio Access Bearer (E-RAB) and oneconcatenation of an S5/S8 bearer.

An RB exists between a UE and a base station and transmits a packet ofan EPS bearer. A specific RB has one-on-one mapping relationship with acorresponding EPS bearer/E-RAB.

An S1 bearer, which is a bearer that exists between an S-GW and a basestation, transmits a packet of an E-RAB.

An S5/S8 bearer is a bearer of an S5/S8 interface. S5 and S8 bearers arebearers that exist for interfaces between S-GW and P-GW. An S5 interfaceexists if the S-GW and the P-GW belong to the same service provider, andan S8 interface exists if the S-GW belongs to a service provider of aroaming service (a visited Public Land Mobile Network (PLMN)) and theP-GW belongs to a subscribed service provider (a Home PLMN).

An E-RAB indicates an S1 bearer and a concatenation of a correspondingRB. If an E-RAB exists, a mapping relationship exists between the E-RABand one EPS bearer. More specifically, one EPS bearer corresponds to oneRB, one S1 bearer, or one S5/S8 bearer. An S1 bearer is a bearer for aninterface between a base station and an S-GW.

As described above, an RB includes a data RB (DRB) and a signaling RB(SRB). However, a DRB provided by Uu interface for supporting a userservice may be referred to as an RB throughout the description.Accordingly, an RB as the DRB needs to be distinguished from the SRB. AnRB is a path through which user plane data is delivered, and an SRB is apath through which control plane data, such control messages of RRClayer and NAS, is delivered. One-on-one mapping relationship existsbetween an RB/E-RAB and an EPS bearer. In order to generate a DRB thatcouples an uplink and a downlink, a base station performs one-on-onemapping between the DRB and an S1 bearer and stores the mapping result.In order to generate an S1 bearer and an S5/S8 bearer that couple anuplink and a downlink, a S-GW performs one-on-one mapping between the S1bearer and the S5/S8 bearer and stores the mapping result.

Types of EPS bearers include a default bearer and a dedicated bearer. Ifa UE accesses a wireless communication network, the UE is assigned withan IP address, a PDN connection is established and a default EPS beareris generated for the UE. The default bearer is generated newly if a newPDN connection is established. If a user starts to use a service inwhich a QoS is not ensured by a default bearer, e.g., a VoD service,while the user is using a service (e.g., an internet, etc.) through thedefault bearer, a dedicated bearer is generated as an on-demand. Thededicated bearer may be configured with different QoS from a QoSconfigured for an existing bearer. The QoS determination parameters forthe dedicated bearer may be provided by a Policy and Charging RuleFunction (PCRF). In order to generate a dedicated bearer, the PCRF maydetermine QoS determination parameters by receiving subscriptioninformation of a user from a Subscriber Profile Repository (SPR). Forexample, the maximum number of generated dedicated bearer may be 15, and4 bearers among the 15 dedicated bearers are not used in an LTE system.Accordingly, the maximum number of generated dedicated bearer may be 11in an LTE system.

An EPS bearer includes QoS Class Identifier (QCI) and Allocation andRetention Priority (ARP) as basic QoS determination parameters. EPSbearers may be classified into a Guaranteed Bit Rate (GBR)-type bearerand a non-GBR-type bearer according to a QCI resource type. A defaultbearer is configured as a non-GBR-type bearer, and a dedicated bearermay be configured as a GBR-type bearer or a non-GBR-type bearer. AGBR-type bearer has GBR and Maximum Bit Rate (MBR) as QoS determinationparameters in addition to the QCI and ARP. After determining a QoSrequirement of a wireless communication system as an EPS bearer, aspecific QoS is determined for each interface. Each interface configuresa bearer according to its own QoS requirement.

FIG. 5 is a diagram illustrating of dual connectivity for a userequipment, according to one or more exemplary embodiments.

As an example, FIG. 5 illustrates a case in which a UE 550 enters anoverlapped area of a service area of a macro cell F2 of a master basestation 500 and a service area of a small cell F1 of a secondary basestation 510.

In this case, in order to support additional data services through thesmall cell F1 of the secondary base station 510 while maintaining anexisting radio connection and a data service connection through themacro cell F2 of the master base station 400, the network configures adual connectivity to the UE 550. Accordingly, user data arrived in themaster base station 500 may be transmitted to the UE 550 through thesecondary base station 510. More specifically, a frequency band of F2 isallocated to the master base station 500, and the frequency band of F1is allocated to the secondary base station 510. The UE 550 may receive aservice via the frequency band of the F1 from the secondary base station510 while receiving a service via the frequency band of the F2 from themaster base station 500. As described above, the master base station 500utilizes the frequency band of the F2 and the secondary base station 510utilizes the frequency band of the F1, but aspects of the presentinvention are not limited as such. Both the master base station 500 andthe secondary base station 510 may utilized the same frequency band ofthe F1 or the F2.

FIG. 6 is a diagram illustrating a user plane structure for dualconnectivity, according to one or more exemplary embodiments.

A UE, a master evolved NodeB (MeNB), and at least one secondary evolvedNodeB (SeNB) may configure for dual connectivity. As shown in FIG. 6,there may be three options for a dual connectivity in accordance with adivision scheme of user plane data. As an example, FIG. 6 illustratesconcepts of the three different options with respect to a downlinktransmission of user plane data.

OPTION 1: The S1-U interface has a master base station and a secondarybase station as terminal nodes. In this option, each base station (MeNBand SeNB each) transmits downlink data via an EPS bearer configured fora UE (EPS bearer #1 for the MeNB, EPS bearer #2 for the SeNB). Since useplane data splits at a Core Network (CN), this option may be referred toas “CN split”.

OPTION 2: The S1-U interface has only master base station as a terminalnode. In this option, although the S1-U interface has only master basestation as a terminal node, each base station is mapped with one bearerwithout splitting the bearers.

OPTION 3: The S1-U interface has only master base station as a terminalnode. In this option, since a bearer splits, this may be referred to as“bearer split”. According to the “bearer split” scheme, since one bearersplits into a plurality of base stations, data is divided into two ormore flows and transmitted. Since data is delivered through a pluralityof flows, the “bearer split” scheme may be referred to as a multi flow,multiple nodes (eNB) transmission, inter-eNB carrier aggregation, andthe like.

With respect to a protocol structure, if the S1-U interface has onlymaster base station as a terminal node (that is, in the case of OPTION 2or OPTION 3), a protocol layer in a secondary base station may berequired to support a segmentation or re-segmentation process. This isbecause a physical interface and the segmentation process are closelyrelated and, a segmentation or re-segmentation process needs tocorrespond to the node transmitting RLC PDUs when a non-ideal backhaulis used. Accordingly, protocol structures for dual connectivity on theRLC layer or an upper layer may be variously configured as the typesdescribed below, for example.

-   -   A. Type 1: a configuration in which PDCP layers are        independently exist in each base station: This configuration may        be referred to as an independent PDCP type. In this        configuration, each base station may utilize the existing LTE        layer 2 protocol operations in a bearer. This configuration may        be utilized in the above described OPTION 1, OPTION 2, and        OPTION 3.    -   B. Type 2: a configuration in which RLC layers are independently        exist in each base station: This configuration may be referred        to as an independent RLC type. In this configuration, the S1-U        interface has only master base station as a terminal node, and a        PDCP layer exist in the master base station only. In the “bearer        split” (OPTION 3) scheme, a network and a UE has a separated RLC        layer, and each RLC layer has an independent RLC bearer.    -   C. Type 3: a configuration in which an RLC layer includes a        ‘master RLC layer’ in a master base station and a ‘slave RLC        layer’ in a secondary base station. This configuration may be        referred to as a master-slave RLC type. In this configuration,        the S1-U interface has only master base station as a terminal        node. The master base station includes a PDCP layer and a part        of an RLC layer (the master RLC layer), and a secondary base        station includes another part of the RLC layer (the slave RLC        layer). A UE includes one RLC layer that is paired with the        master RLC layer and the slave RLC layer.

Accordingly, the dual connectivity configurations may vary in accordancewith different combinations of the above mentioned options and types asfollowing FIG. 7 and/or FIG. 8.

FIG. 7 and FIG. 8 are diagrams illustrating protocol structures of basestations in the case of downlink data transmission for a user plane,according to one or more exemplary embodiments.

Referring to FIG. 7, the S1-U interface has a master base station and asecondary base station as terminal nodes, and each base station has anindependent PDCP layer (the independent PDCP type). In thisconfiguration, each of the master base station and the secondary basestation includes a PDCP layer, an RLC layer, and a MAC layer, and eachbase station transmits downlink data via the respective EPS bearerconfigured for a UE. Such a structure may be referred to as a dualconnectivity mode 1A.

In this configuration, it may not be necessary for a master base stationto buffer or process packets delivered by a secondary base station, andthere may be an advantage that there is no, or insignificant, impact onRDCP/RLC and GTP-U/UDP/IP. Furthermore, there may be fewer requirementsbetween backhaul link of a master base station and a secondary basestation. There may be an advantage that a secondary base station cansupport local break-out and content caching for a UE connected by a dualconnectivity function and a master base station does not need to routeall traffics because a flow between a master base station and asecondary base station does not need to be controlled.

Referring to FIG. 8, the S1-U interface has only a master base stationas terminal nodes, a bearer split is not performed, and PDCP layersindependently exist in each base station (the independent PDCP type). Inthis case, PDCP layers, RLC layers, and MAC layers exist in a masterbase station, and secondary base station may include an RLC layer and aMAC layer without having a PDCP layer. The PDCP layers, the RLC layers,and the MAC layers in the master base station may be divided into bearerlevels, respectively, and one of the PDCP layers may be connected to anRLC layer of the master base station and may be connected an RLC layerof the secondary base station through Xn (or X2) interface. Such astructure may be referred to as a dual connectivity mode 3C.

Such case has the merit of the mobility of the secondary base stationbeing hidden in the core network, has insignificant or no effect on asecurity issue for the master base station to require an encryption, andhas the merit of eliminating the need of data forwarding betweensecondary base stations when a secondary base station needs to bechanged. Further, the structure enables the master base station toassign an RLC processing to the secondary base station in the dualconnectivity configuration, has insignificant or no effect on RLC, andenables radio resources being utilized through the master base stationand the secondary base station with respect to the same bearer whenpossible. Also, it has the merit of relatively lenient mobilityrequirements for the secondary base station because it enables the useof mater base station during the movement between secondary basestations.

FIG. 9 is a diagram illustrating an example of a Media Access Control(MAC) entity architecture corresponding to the protocol architectures ofFIG. 7 and FIG. 8, according to one or more exemplary embodiments.Operations of a UE may be defined based on the MAC entity architecturefor uplink transmission of the UE of FIG. 9.

Referring to FIG. 9, a first embodiment shows that a MAC entity isconfigured in only a bearer for a Master eNB (MeNB). The firstembodiment may be applied to all the protocol architectures of FIGS. 7and 8, in association with an uplink. A second embodiment shows that aMAC entity is configured in bearers for both a MeNB and a Secondary eNB(SeNB) (that is, bearer split), and may be applied to the protocolarchitecture of FIG. 8. A third embodiment shows that a MAC entity isconfigured in only a bearer for a SeNB, and may be applied to theprotocol architecture of FIG. 7.

FIG. 10 is a diagram illustrating another example of a MAC entityarchitecture corresponding to the protocol architectures of FIG. 7 andFIG. 8, according to one or more exemplary embodiments. Operations of aUE may be defined based on the MAC entity architecture for downlinktransmission to the UE of FIG. 10.

Referring to FIG. 10, a first embodiment shows that a MAC entity isconfigured in only a bearer for a MeNB. The first embodiment may beapplied to the protocol architecture of FIG. 7, in association with adownlink. A second embodiment shows that a MAC entity is configured inbearers for both a MeNB and a Secondary eNB (SeNB) (that is, bearersplit), and may be applied to the protocol architecture of FIG. 8. Athird embodiment shows that a MAC entity is configured in only a bearerfor a SeNB, and may be applied to the protocol architecture of FIG. 7.

Hereinafter, Carrier Aggregation (CA) will be described in more detail.The CA scheme is a technology to effectively use divided narrow bands,and the CA scheme may provide an effect that a base station uses alogically wide band by aggregating physically continuous ornon-continuous bands in a frequency domain. The frequency bands used forthe CA may be referred to as a Component Carrier (CC), respectively.

Component carriers may be classified into a Primary Component Carrier(PCC) and a Secondary Component Carrier (SCC). A UE may use only PCC ormay use one or more SCCs along with the PCC. A UE may be assigned thePCC and/or SCC(s) from a base station.

When a CA is configured for a UE, the UE has one RRC connection with anetwork. This applies even when dual connectivity is configured for theUE. In a case where an RRC connection is established or re-establishedor a handover occurs, a specific serving cell may provide the UE withnon-access stratum (NAS) mobility information (e.g., Tracking Area ID(TAI)). Hereinafter, the specific serving cell is referred to as aPrimary serving Cell (PCell) and serving cells other than the PCell arereferred to as Secondary serving Cells (SCells). For the PCell, a pairof Downlink Primary Component Carrier (DL PCC) and Uplink PrimaryComponent Carrier (UL PCC).

According to UE capability, secondary serving cells may be configured,with the PCell, in a serving cell group. Only DL Secondary ComponentCarrier (DL SCC) may be configured for a secondary serving cell, only ULSCC may be configured for a secondary serving cell, or a pair of DL SCCand UL SCC may be configured for a secondary serving cell. The servingcell group may include one PCell and at least one SCell. PCell may bechanged only thorough a handover procedure, and may be used for aPhysical Uplink Control CHannel (PUCCH) transmission. Although PCellcannot be deactivated, an SCell may be changed to a deactivated state.

Addition/elimination/reconfiguration of a secondary serving cell may beperformed through a dedicated signaling, an RRC connectionreconfiguration procedure. If a new secondary serving cell is configuredfor a UE, system information of the new secondary serving cell may alsobe included in an RRC connection reconfiguration message and transmittedto the UE through the RRC connection reconfiguration procedure.Accordingly, a secondary serving cell does not need to monitor a changeof system information.

Hereinafter, Power Headroom (PH) will be described.

The PH refers to residual power that a current UE may afford to utilize,in addition to power that the current UE currently uses for uplinktransmission. For example, it is assumed that a maximum transmissionpower which is an uplink transmission power within a range allowed to aUE, is 10 W, and the UE currently consumes power of 9 W in a frequencyband of 10 Mhz. In this instance, the UE may afford 1W, additionally,and thus, the PH is 1 W.

Here, when an eNB allocates a frequency band of 20 Mhz to a UE, power of18 W(=9 W×2) may be required. However, the maximum power of the UE is 10W and thus, when 20 Mhz is allocated to the UE, the UE may fail to usethe entire frequency band or the eNB may fail to receive a signal of theUE due to lack of power. To overcome the above drawbacks, the UE reportsto the eNB that the PH is 1 W, so that the eNB executes schedulingwithin the range of PH. The report is referred to as a Power HeadroomReport (PHR).

Through the PHR, 1) information associated with a difference between thenominal maximum transmission power of a UE for each activated servingcell and an estimated UL-SCH (PUSCH) transmission power, 2) informationassociated with a difference between the nominal maximum transmissionpower of a UE for a Primary serving cell (PCell) and a estimated PUCCHtransmission power, or 3) information associated with a differencebetween the nominal maximum transmission power for a PCell and anestimated UL-SCH and PUCCH transmission power, may be transmitted to aserving eNB.

The PHR of a UE may be defined as two types (type 1 and type 2). The PHof a UE may be defined with respect to a subframe i for a serving cellc. Type 1 PH corresponds to 1) the case where a UE transmits only aPUSCH without a PUCCH, 2) the case where a UE simultaneously transmits aPUCCH and a PUSCH, and 3) the case where a PUSCH is not transmitted.Type 2 PH corresponds to 1) the case where a UE simultaneously transmitsa PUCCH and a PUSCH, 2) the case where a UE transmits a PUSCH without aPUCCH, 3) the case where a UE transmits a PUCCH without a PUSCH, and 4)the case where a UE does not transmit a PUCCH or a PUSCH, with respectto a subframe i for a PCell.

When an extended PHR is not configured, only the type 1 PHR associatedwith the PCell is reported. Conversely, when the extended PHR isconfigured, the type 1 PH and the type 2 PH are reported to activatedserving cells for which an uplink is configured, respectively.

PH reporting delay refers to a difference between a point where a PHreference section begins and a point where a UE beings transmission of aPH value through a wireless interface. The PH reporting delay needs tobe 0 ms, and this may be applied to all triggering schemes configuredfor PHR.

The PHR may be controlled by a periodic PHR-timer (hereinafter, referredto as a periodic timer), and a prohibit PHR-timer. Triggering of the PHRin association with a change in a pathloss measured by a UE in adownlink and a change of a power management-based backoff required value(P-MPR), is controlled by transmitting dl-PathlossChange through an RRCmessage.

A reported PH is mapped as a predetermined index value, which is listedas shown in the following table.

TABLE 1 Reported value Measured quantity value (dB) POWER_HEADROOM_0 −23≦ PH < −22 POWER_HEADROOM_1 −22 ≦ PH < −21 POWER_HEADROOM_2 −21 ≦ PH <−20 POWER_HEADROOM_3 −20 ≦ PH < −19 POWER_HEADROOM_4 −19 ≦ PH < −18POWER_HEADROOM_5 −18 ≦ PH < −17 . . . . . . POWER_HEADROOM_57 34 ≦ PH <35 POWER_HEADROOM_58 35 ≦ PH < 36 POWER_HEADROOM_59 36 ≦ PH < 37POWER_HEADROOM_60 37 ≦ PH < 38 POWER_HEADROOM_61 38 ≦ PH < 39POWER_HEADROOM_62 39 ≦ PH < 40 POWER_HEADROOM_63 PH = 40

Referring to Table 1, the PH is included in the range from −23 dB to +40dB. When 6 bits are used for expressing a PH, 64 (=26) indices areexpressed, and thus, PHs may be classified into a total of 64 levels.For example, when a bit that expresses a PH is ‘0’ (‘000000’ whenexpressed in 6 bits), this indicates that the level of the PH is‘−23≦P_(PH)≦−22 dB.’

The power limited case refers to the case where a required transmissionpower of a UE indicated by an eNB is higher than a maximum transmissionpower allowed for the UE while the UE executes uplink transmission, andthe required transmission power is limited. In this instance, a PH valuein a form of negative number may be reported.

Conversely, the non-power limited case refers to the case where arequired transmission power of a UE indicated by an eNB is lower than amaximum transmission power allowed for the UE while the UE executesuplink transmission, and the required transmission power is not limited.In this instance, a PH value in a form of positive number may bereported.

Hereinafter, power scaling will be described. Power scaling refers toreduction of a transmission power based on a predetermined scale, so asto allocate power that does not exceed a total transmit power of a UE.An example of power scaling is multiplexing an original transmissionpower by a scaling factor. The power scaling may be variously expressedby power adjustment, power scaling, power control, or the like.

When a total transmit power of a UE exceeds {circumflex over(P)}_(CMAX)(i), the UE executes scaling with respect to {circumflex over(P)}_(PUSCH,c)(i) of a subframe i for a serving cell c, as shown inEquation 1 provided below.

$\begin{matrix}{{\sum\limits_{c}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Referring to Equation 1, {circumflex over (P)}_(PUCCH)(i) is a linearvalue of P_(PUCCH)(i), and P_(PUCCH)(i) is a PUCCH transmission power ina subframe i. {circumflex over (P)}_(PUSCH,c)(i) is a linear value ofP_(PUSCH,c)(i) that is a PUSCH transmission power for a serving cell cin a subframe i, {circumflex over (P)}_(CMAX)(i) is a linear value of atotal configured maximum output power (or maximum transmission power)P_(CMAX), configured for a UE in a subframe i, and w(i) denotes ascaling factor of {circumflex over (P)}_(PUSCH,c)(i) for a serving cellc, and has a value from 0 to 1. When a PHCCH transmission does not existin the subframe i, {circumflex over (P)}_(PUCCH)(i)=0.

When a UE has a PUSCH transmission with Uplink Control Information (UCI)in a serving cell j, has a PUSCH transmission without UCI in any of theremaining serving cells, and the total transmit power of the UE exceeds{circumflex over (P)}_(CMAX)(i), the UE may execute scaling of{circumflex over (P)}_(PUSCH,c)(i) with respect to serving cells thatcarry a PUSCH without UCI of a subframe i, as shown in Equation 2provided below.

$\begin{matrix}{{\sum\limits_{c \neq j}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUSCH},j}(i)}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

Here, {circumflex over (P)}_(PUSCH,j)(i) is a linear value of a PUSCHtransmission power with respect to a cell with UCI, and w(i) denotes ascaling factor of {circumflex over (P)}_(PUSCH,c)(i) with respect to aserving cell c without UCI. In this instance, when

${\sum\limits_{c \neq j}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} = 0$

is not satisfied, a total transmit power of the UE does not exceed{circumflex over (P)}_(CMAX)(i), power scaling is not applied to{circumflex over (P)}_(PUSCH,j)(i).

When w(i) is greater than 0, w(i) is equal with respect to servingcells. In this instance, however, w(i) may be 0 with respect topredetermined serving cells.

When a UE simultaneously transmits a PUCCH and a PUSCH with UCI in aserving cell j, transmits a PUSCH without UCI in any of the remainingserving cells, and a total transmit power of the UE exceeds {circumflexover (P)}_(CMAX)(i), the UE may obtain {circumflex over(P)}_(PUSCH,c)(i) as shown in Equation 3 provided below.

$\begin{matrix}{{{{\hat{P}}_{{PUSCH},j}(i)} = {\min \left( {{{\hat{P}}_{{PUSCH},j}(i)},\left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)}} \right)} \right)}}{{\sum\limits_{c \neq j}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{\hat{P}}_{{PUSCH},j}(i)}} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

When a UE that supports CA executes communication with a plurality ofeNBs based on dual connectivity, a plurality of aggregated serving cellsmay be provided through different eNBs. Among serving cells configuredfor a UE, a serving cell group that is provided by a MeNB is referred toas a Master Cell Group (MCG), and a serving cell group that is providedby the SeNB is referred to as a Secondary Cell Group (SCG). For example,it is assumed that a PCell, a first SCell, and a second SCell areconfigured for a UE through the CA. In the dual connectivity situation,the PCell and the first SCell may be included in the MCG provided by theMeNB, and the second SCell may be included in the SCG provided by theSeNB.

For the UE having dual connectivity, the MeNB and the SeNB may executeindependent scheduling with respect to the UE. That is, the UE havingdual connectivity, may be connected to at least two eNBs havingindependent schedulers, and transmit and receive data. In this instance,the MCG and the SCG may operate based on QoSs independent from oneanother.

Each of the MCG and the SCG may have a serving cell for executing atleast one PUCCH transmission, so as to effectively report a HARQACK/NACK. For example, a PUCCH may be transmitted in both a PCellincluded in the MCG and a predetermined small cell included in the SCG.That is, in some cases, a UE may execute simultaneous PUCCH transmissionon two serving cells, in a single subframe. Therefore, thecharacteristics of dual connectivity should be taken into consideration,to execute transmission power control (and power scaling) for a UE. Inaddition, transmission of a PRACH, a PUSCH, a Sounding Reference Signal(SRS), a Demodulation Reference Signal (DMRS), and the like, based ondual connectivity, should be taken into account.

Accordingly, the present invention provides a transmission powercontrolling method for a UE by taking into consideration dualconnectivity. Particularly, in the case where power of a UE for whichdual connectivity is configured, is limited (for example, the case wherea total transmit power of the UE exceeds {circumflex over(P)}_(CMAX)(i)), a power control (and scaling) method for a UE toexecute uplink transmission to a plurality of eNBs through a pluralityof uplink channels in a single subframe, is provided.

Various methods may be used to execute PUSCH/PUCCH power control (andscheduling) for a UE for which dual connectivity is configured underpower limited case, and the methods may be classified based on thenumber of cell groups through which a PUSCH that carries UCI istransmitted in a single subframe, as follows. (1) For example, a PUSCHtransmission with UCI does not exist in a corresponding subframe(hereinafter referred to as Case 1). (2) As another example, a PUSCHtransmission with UCI in a corresponding subframe exists in only asingle cell group (hereinafter referred to as Case 2). (3) As anotherexample, a PUSCH transmission with UCI in a corresponding subframeexists in all cell groups (hereinafter referred to as Case 3). In theabove examples, a PUCCH(s) and a PUSCH(s) without UCI may or may not betransmitted.

Table 2 lists examples of the cases where PUSCH/PUCCH power control (andscaling), which is classified based on the number of cell groups where aPUSCH that carries UCI is transmitted, is applied.

TABLE 2 MeNB SeNB PUSCH w/ PUSCH PUSCH PUSCH w/ PUSCH PUSCH PUCCH UCIw/o UCI#0 w/o UCI#1 PUCCH UCI w/o UCI#0 w/o UCI#1 case ◯* ◯ ◯* ◯* case 1◯* ◯* ◯ ◯* ◯* ◯ ◯* ◯* ◯ ◯* ◯* ◯ ◯* ◯* ◯* ◯* ◯* case 2 ◯* ◯* ◯* ◯* ◯ ◯*◯* ◯* ◯ ◯* ◯* ◯* ◯ ◯* ◯* case 3 *denotes a channel that may or may notbe transmitted

Referring to Table 2, O denotes a channel that is transmitted in anuplink, and O* denotes a channel that may or may not be transmitted.PUSCH w/ UCI denotes a PUSCH with UCI, and PUSCH w/o UCI#n denotes aPUSCH without UCI. PUSCH w/o UCI#0 indicates that a PUSCH without UCI istransmitted in a serving cell of a corresponding cell group, and PUSCHw/o UCI#1 may indicate that a PUSCH without UCI is transmitted inanother serving cell of the corresponding cell group.

For example, referring to Case 3, a PUSCH with UCI (PUSCH w/ UCI) istransmitted to each of an MeNB and an SeNB, and the remaining PUCCH andPUSCH (PUSCH w/o UCI#n) may or may not be transmitted.

When power control (and scaling) is executed, a power allocationpriority is defined and power control (and scaling) may be executedbased on the priority. When dual connectivity is configured for a UE,the priority in the power limited case may be listed as follows.

TABLE 3 Priority Example PUCCHs > PUSCH w/ UCI for MCG > PUSCH w/ UCIfor SCG > Priority 1 PUSCH w/o UCI for MCG > PUSCH w/o UCI for SCGExample PUCCHs > PUSCH w/ UCI for MCG > PUSCH w/ UCI for SCG > Priority1′ PUSCH w/o UCI for MCG = PUSCH w/o UCI for SCG Example PUCCHs > PUSCHw/ UCI for MCG = PUSCH w/ UCI for SCG > Priority 2 PUSCH w/o UCI forMCG > PUSCH w/o UCI for SCG Example PUCCHs > PUSCH w/ UCI for MCG =PUSCH w/ UCI for SCG > Priority 2′ PUSCH w/o UCI for MCG = PUSCH w/o UCIfor SCG Example PUCCHs > PUSCH w/ UCI for MCG > PUSCH w/ UCI for SCG >Priority 3 PUSCH w/o UCI for a cell group with Higher QoS > PUSCH w/oUCI for a cell group with lower QoS Example PUCCHs > PUSCH w/ UCI forMCG = PUSCH w/ UCI for SCG > Priority 4 PUSCH w/o UCI for a cell groupwith Higher QoS > PUSCH w/o UCI for a cell group with lower QoS

In Table 3, referring to the example 1, PUCCH power is allocatedpreferentially, and a PUSCH with UCI of an MCG, a PUSCH with UCI of anSCG, a PUSCH without UCI of the MCG, and a PUSCH without UCI of the SCGare allocated sequentially.

Referring to the example 2, PUCCH power is allocated preferentially, aPUSCH with UCI of the MCG and a PUSCH with UCI of the SCG are allocatedsubsequently, a PUSCH without UCI of the MCG is allocated subsequently,and a PUSCH without UCI of the SCG is allocated subsequently.

The example 1′ and the example 2′ are modulated from the example 1 andthe example 2, respectively, so that the PUSCH without UCI of the MCGand the PUSCH without UCI of the SCG have an identical priority.

Referring to the example 3, PUCCH power is allocated preferentially, anda PUSCH with UCI of the MCG, a PUSCH with UCI of the SCG, a cell grouphaving the highest QoS from among the MCG and the SCG, a cell grouphaving the lowest QoS from among the MCG and the SCG, are allocatedsequentially.

Referring to the example 4, PUCCH power is allocated preferentially, aPUSCH with UCI of the MCG and a PUSCH with UCI of the SCG are allocatedsubsequently, a cell group having the highest QoS from among the MCG andthe SCG is allocated subsequently, and a cell group having the lowestQoS from among the MCG and the SCG is allocated subsequently.

As described in the example 3 and the example 4, when the priority forPUSCH power scaling is determined based on a QoS, a first layer (L1) isnot aware of a QoS value and thus, may receive corresponding informationfrom a higher layer. For example, a physical layer of a UE may receivean indication of a QoS value associated with the MCG and the SCG, froman RRC layer or a MAC layer.

Although descriptions are provided based on a PUSCH in the examples, aPUCCH of the MCG may have a higher priority between the PUCCH of the MCGand a PUCCH of the SCG, and the priority of a PUCCH for a predeterminedcell group may be higher than the priority of a PUCCH for another cellgroup, based on characteristics of UCI transmitted through the PUCCH.Also, the priority of a PUSCH may be changed based on thecharacteristics of UCI that is transmitted through the correspondingPUSCH with UCI. Examples of priorities determined based on thecharacteristics of UCI may include SR>HARQ-ACK>CSI report type 3, 5, 6,or 2a>CSI report type 1, 1a, 2, 2b, 2c, or 4. Priorities of PUCCHs andPUSCHs with UCI may be determined based on the priories determined basedon the characteristic of UCI. As a matter of course, a PUSCH without UCIhas a relatively low priority. Among PUSCHs without UCI, priorities maybe determined based on whether it belongs to MCG/SCG or based on a QoSlevel.

Hereinafter, PUSCH/PUCCH power control (and scaling) methods accordingto the present invention will be described, and at least one of thepriorities may be applied to the methods of the present invention. Inaddition, the PUSCH/PUCCH power control (and scaling) methods assume thepower limited case with respect to a UE.

Case 1: No PUSCH Transmission with UCI

(1) Method 1: No PUCCH Power Scaling

When a PUSCH transmission with UCI does not exist in a subframe i and atotal transmit power of a UE exceeds {circumflex over (P)}_(CMAX)(i),the UE executes power scaling of {circumflex over (P)}_(PUSCH,k,c)(i)with respect to a serving cell c in the subframe i of a MCG and an SCG,as shown in Equation 4 provided below.

$\begin{matrix}{{\sum\limits_{k}\; {\sum\limits_{c}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}\; {{\hat{P}}_{{PUCCH},k}(i)}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack\end{matrix}$

Referring to Equation 4 and {circumflex over (P)}_(PUCCH,k)(i) is alinear value of P_(PUCCH,k)(i) and P_(PUCCH,k)(i) denotes a PUCCHtransmission power in a subframe i with respect to an eNB or a cellgroup k. {circumflex over (P)}_(PUSCH,k,c)(i) is a linear value ofP_(PUSCH,k,c)(i). P_(PUSCH,k,c)(i) denotes a PUSCH transmission powerfor a serving cell c, in a subframe i for an eNB or a cell group k. kdenotes an eNB or cell group indicator. k denotes an eNB indicatorindicating an eNB to which (a cell group through which) a PUSCH istransmitted from among eNBs (MeNB and SeNB) or (cell groups (MCG andSCG)) having dual connectivity. For example, k=0 indicates a MeNB or aMCG, and k=1 indicates a SeNB or a SCG. {circumflex over (P)}_(CMAX)(i)is a linear value of a total configured maximum output power P_(CMAX),configured for a UE in a subframe i. w_(k)(i) denotes a scaling factorof {circumflex over (P)}_(PUSCH,k,c)(i) with respect to a serving cell cassociated with a predetermined eNB or cell group. w_(k)(i) has a valuefrom 0 to 1 (0≦w_(k)(i)≦1). w_(k)(i) has an identical value with respectto all serving cells in a single eNB (or a single cell group). That is,w_(k)(i) is an eNB (or cell group)-specific parameter. When a PUCCHtransmission does not exist in a subframe i with respect to acorresponding eNB or cell group, {circumflex over (P)}_(PUCCH,k)(i) maybe 0. For example, when a PUCCH transmission does not exist in thesubframe i with respect to a MCG, {circumflex over(P)}_(PUCCH,k=0)(i)=0, and when a PUCCH transmission does not exist inthe subframe i with respect to a SCG, {circumflex over(P)}_(PUCCH,k=1)(i)=0.

Basically, the method prioritizes a PUCCH transmission over a PUSCHtransmission, irrespective of a cell group in dual connectivity. Themethod does not execute PUCCH power scaling. Case 1 does not include aPUSCH transmission with UCI, and thus, PUSCH power scaling may beexecuted by applying an independent scaling factor w_(k)(i) to a PUSCHtransmission, for each eNB (or each cell group) in dual connectivity.

When PUSCHs without UCI are transmitted over a plurality of servingcells in a single cell group, equal scaling may be executed with respectto the transmission of PUSCHs, like the scaling method used for theexisting uni-connectivity.

In addition, as described above, independent scheduling based ondifferent QoSs may be supported for a UE for which dual connectivity isconfigured. In this instance, different power scaling may be supportedbased on a MCG or a SCG. Therefore, w_(k)(i), which is an eNB (or cellgroup)-specific parameter, may be used.

For example, Case 1 does not transmit a PUSCH with UCI in a MCG and aSCG, and thus, a smaller power scaling may be applied to a PUSCHtransmission in the MCG where an RRC message is transmitted or a PUSCHtransmission in a cell group (MCG or SCG) having a relatively higherQoS. When a smaller power scaling is applied, a relatively higher powermay be allocated. That is, the PUSCH transmission in the MCG where anRRC message is transmitted or the PUSCH transmission in the cell group(MCG or SCG) having a relatively higher QoS may have a higher priority.

FIG. 11 shows two diagrams illustrating examples of non-equal powerscaling between cell groups for Case 1, according to one or moreexemplary embodiments. In FIG. 11's embodiments may assume power scalingwith respect to a PUSCH transmission without UCI. In FIG. 11, CC1 andCC2 of an MeNB belongs to an MCG, and CC1 and CC2 of an SeNB belongs toan SCG.

(a) in the FIG. 11 is the case where an RRC message is transmitted inonly CC1 of an MeNB, and (b) in the FIG. 11 is the case where an RRCmessage is transmitted in both CC1 and CC2 of a MCG of the MeNB. Basedon the embodiment of a UE and an eNB, the RRC Message may be transmittedthrough a single cell (CC1) of the MCG, or may be transmitted throughtwo cells (CC1 and CC2) of the MCG.

A smaller power scaling (that is, applying a large scaling factor) maybe executed with respect to a PUSCH transmission without UCI in the MCGwhere an RRC message may be transmitted, as illustrated in FIG. 11. Thatis, the PUSCH transmission without UCI in the MCG may have a higherpriority than a PUSCH transmission without UCI in an SCG. Alternatively,a smaller power scaling may be executed with respect to a PUSCHtransmission without UCI in a cell group having a higher QoS. That is,the PUSCH transmission without UCI in the cell group having a higher QoSmay have a higher priority than a PUSCH transmission without UCI in acell group having a lower QoS.

(2) Method 2: PUCCH Power Scaling

Equation 4 of Method 1 does not take into account power scaling withrespect to a PUCCH transmission, and only takes into consideration powerscaling with respect to a PUSCH transmission without UCI even thoughPUCCH transmission occurs in both of the two cell groups. Underassumption that a PUCCH transmission in each cell group is power scaled,when a PUSCH transmission with UCI does not exist in a subframe i and atotal transmit power of a UE exceeds {circumflex over (P)}_(CMAX)(i),the UE may execute power scaling of {circumflex over (P)}_(PUCCH,k)(i)and {circumflex over (P)}_(PUSCH,k,c)(i) with respect to a serving cellc, in the subframe i with respect to an MCG and an SCG, as shown inEquations 5 and 6.

$\begin{matrix}{\mspace{79mu} {{\sum\limits_{k}\; {{g_{k}(i)} \cdot {{\hat{P}}_{{PUCCH},k}(i)}}} \leq {{\hat{P}}_{CMAX}(i)}}} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack \\{{\sum\limits_{k}\; {\sum\limits_{c}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}\; {{g_{k}(i)} \cdot {{\hat{P}}_{{PUCCH},k}(i)}}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 6} \right\rbrack\end{matrix}$

Referring to Equation 5 and Equation 6, g_(k)(i) is a scaling factor for{circumflex over (P)}_(PUCCH,k)(i). g_(k)(i) has a value from 0 to 1(0≦g_(k)(i)≦1). k in g_(k)(i) indicates a predetermined eNB or cellgroup. That is, gk(i) may be used for power scaling for a PUCCHtransmitted over a predetermined eNB or cell group. g_(k)(i) values foran MeNB (or MCG) and an SeNB (or SCG) may or may not be identical. Forexample, when an identical g_(k)(i) value is used for the MeNB (or MCG)and the SeNB (or SCG), it may be expressed as g(i). When a PUCCHtransmission does not exist in a subframe i with respect to acorresponding eNB or cell group, {circumflex over (P)}_(PUCCH,k)(i) maybe 0. For example, when a PUCCH transmission does not exist in thesubframe i with respect to a MCG, {circumflex over(P)}_(PUCCH,k=0)(i)=0, and when a PUCCH transmission does not exist inthe subframe i with respect to a SCG, {circumflex over(P)}_(PUCCH,k=1)(i)=0.

(3) Method 3: The Case that Prioritizes a PUCCH Transmission of aPredetermined Cell Group

Method 3 does not use a separate scaling factor g_(k)(i) for a PUCCH,unlike Method 2. Method 3 prioritizes a PUCCH transmission correspondingto a predetermined cell group, sets a PUCCH transmission correspondingto the remaining cell group to have a subsequent priority, performspower allocation, and executes scaling for a PUSCH transmission withoutUCI based on w_(k)(i). In this instance, control of {circumflex over(P)}_(PUCCH,k)(i) and {circumflex over (P)}P_(PUSCH,k,c)(i) may beexecuted based on Equation 7 and Equation 8, provided below.

$\begin{matrix}{{{\hat{P}}_{{PUCCH},{k = 1}}(i)} = {\min \left( {{{\hat{P}}_{{PUCCH},{k = 1}}(i)},\left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUCCH},{k = 0}}(i)}} \right)} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack \\{{\sum\limits_{k}\; {\sum\limits_{c}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}{{\hat{P}}_{{PUCCH},k}(i)}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack\end{matrix}$

Referring to Equation 7, through min operation, only when {circumflexover (P)}_(PUCCH,k=1)(i) is greater than {circumflex over(P)}_(CMAX)(i)−{circumflex over (P)}_(PUCCH,k=1)(i), {circumflex over(P)}_(PUCCH,k=1)(i) may be adjusted to {circumflex over(P)}_(CMAX)(i)−{circumflex over (P)}_(PUCCH,k=1)(i).

In Equation 7 and Equation 8, when a PUCCH transmission does not existin a subframe i for an MCG, {circumflex over (P)}_(PUCCH,k=0)(i)=0, andwhen a PUCCH transmission does not exist in a subframe i for an SCG,{circumflex over (P)}_(PUCCH,k=1)(i)=0. When a PUCCH transmission doesnot exist in a subframe i for both the MCG and the SCG, {circumflex over(P)}_(PUCCH,k)(i)=0.

(4) Method 4: The Case where a PUSCH Transmission without UCI isExecuted in Only a Single Cell Group (MCG or SCG), and PUCCH PowerScaling is not Executed (not PUCCH Power Scaling)

When a PUSCH transmission with UCI does not exist in a subframe i, aPUSCH transmission without UCI is executed in only a single cell group(MCG or SCG), and a total transmit power of a UE exceeds {circumflexover (P)}_(CMAX)(i), the UE may execute power scaling of {circumflexover (P)}_(PUSCH,k,c)(i) with respect to a serving cell, in a subframe ifor only the single cell group, as shown in Equation 9 provided below.

$\begin{matrix}{{\sum\limits_{c}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}{{\hat{P}}_{{PUCCH},k}(i)}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

Here, k is 0 or 1, and the value may be determined based on the cellgroup where a PUSCH without UCI is transmitted. For example, when aPUSCH without UCI is transmitted in an MCG, k=0. Alternatively, when aPUSCH without UCI is transmitted in an SCG, k=1. The k valuecorresponding to the MCG/SCG is merely an example, which may bedifferently determined based on the agreement between an eNB and a UE.When a PUCCH transmission does not exist in a subframe i for the MCG,{circumflex over (P)}_(PUCCH,k=0)(i)=0, and when a PUCCH transmissiondoes not exist in a subframe i for the SCG, {circumflex over(P)}_(PUCCH,k=1)(i)=0.

The method basically prioritizes a PUCCH transmission over a PUSCHtransmission. The method does not execute PUCCH power scaling.

When PUSCHs without UCI are transmitted over a plurality of servingcells in a single cell group, equal scaling may be executed with respectto the transmission of PUSCHs.

(5) Method 5: The Case where a PUSCH Transmission without UCI isExecuted in Only a Single Cell Group (MCG or SCG), and PUCCH PowerScaling is Executed

Equation 9 of Method 4 does not take into account power scaling withrespect to a PUCCH transmission, and only takes into consideration powerscaling with respect to a PUSCH transmission without UCI even thoughPUCCH transmission occurs in both of the two cell groups. Underassumption that a PUCCH transmission is also power scaled, when a PUSCHtransmission with UCI does not exist in a subframe i, a PUSCHtransmission without UCI is executed in only a single cell group (MCG orSCG), and a total transmit power of a UE exceeds {circumflex over(P)}_(CMAX)(i), the UE may execute power scaling of {circumflex over(P)}_(PUCCH,k)(i) and {circumflex over (P)}_(PUSCH,k,c)(i) with respectto a serving cell c, in the subframe i with respect to an MCG and anSCG, as shown in Equations 10 and 11.

$\begin{matrix}{\mspace{79mu} {{\sum\limits_{k}\; {{w_{{PUCCH},k}(i)} \cdot {{\hat{P}}_{{PUCCH},k}(i)}}} \leq {{\hat{P}}_{CMAX}(i)}}} & \left\lbrack {{Equation}\mspace{14mu} 10} \right\rbrack \\{{\sum\limits_{c}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}\; {{w_{{PUCCH},k}(i)} \cdot {{\hat{P}}_{{PUCCH},k}(i)}}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 11} \right\rbrack\end{matrix}$

Here, w_(PUCCH,k)(i) is a scaling factor for {circumflex over(P)}_(PUCCH,k)(i). w_(PUCCH,k)(i) has a value from 0 to 1(0≦w_(PUCCH,k)(i)≦1). k in w_(PUCCH,k)(i) may indicate a predeterminedeNB or cell group. That is, wPUCCH,k(i) may be used for power scalingfor a PUCCH transmitted over a predetermined eNB or cell group.w_(PUCCH,k)(i) values for an MeNB (or MCG) and an SeNB (or SCG) may ormay not be identical. w_(PUCCH,k)(i) may be interchangeably used withg_(k)(i). When a PUCCH transmission does not exist in a subframe i forthe MCG, {circumflex over (P)}_(PUCCH,k=0)(i)=0, and when a PUCCHtransmission does not exist in a subframe i for the SCG, {circumflexover (P)}_(PUCCH,k=1)(i)=0. When a PUCCH transmission does not exist ina subframe i for both the MCG and the SCG, {circumflex over(P)}_(PUCCH,k)(i)=0.

(6) Method 6: The Case where a PUSCH Transmission without UCI isExecuted in Only a Single Cell Group (MCG or SCG), and Prioritizes aPUCCH Transmission of a Predetermined Cell Group

Method 6 does not use a separate scaling factor w_(PUCCH,k)(i) for aPUCCH, unlike Method 5. Method 6 prioritizes a PUCCH transmissioncorresponding to a predetermined cell group, sets a PUCCH transmissioncorresponding to the remaining cell group to have a subsequent priority,performs power allocation, and executes scaling for a PUSCH transmissionwithout UCI based on w_(k)(i). In this instance, control of {circumflexover (P)}_(PUCCH,k)(i) and {circumflex over (P)}_(PUSCH,k,c)(i) may beexecuted based on Equation 12 and Equation 13 provided below.

$\begin{matrix}{{{\hat{P}}_{{PUCCH},{k = 1}}(i)} = {\min \left( {{{\hat{P}}_{{PUCCH},{k = 1}}(i)},\left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUCCH},{k = 0}}(i)}} \right)} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 12} \right\rbrack \\{{\sum\limits_{c}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}\; {{w_{{PUCCH},k}(i)} \cdot {{\hat{P}}_{{PUCCH},k}(i)}}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 13} \right\rbrack\end{matrix}$

Here, when a PUCCH transmission does not exist in a subframe i for theMCG, {circumflex over (P)}_(PUCCH,k=0)(i)=0, and when a PUCCHtransmission does not exist in a subframe i for the SCG, {circumflexover (P)}_(PUCCH,k=1)(i)=0. When a PUCCH transmission does not exist ina subframe i for both the MCG and the SCG, {circumflex over(P)}_(PUCCH,k)(i)=0.

Case 2: PUSCH Transmission with UCI Exists in Only a Single Cell Group

(1) Method 1: No PUCCH Power Scaling

When a UE simultaneously transmits a PUCCH and a PUSCH with UCI in aserving cell j in a single cell group, transmits a PUSCH without UCI inany of the remaining serving cells (serving cells in the other cellgroup), and a total transmit power of the UE exceeds {circumflex over(P)}_(CMAX)(i), the UE may obtain {circumflex over (P)}_(PUSCH,k) _(UCI)_(,j)(i) and {circumflex over (P)}_(PUSCH,k,c)(i) as shown in equationsprovided below.

$\begin{matrix}{{{\hat{P}}_{{PUSCH},k_{UCI},j}(i)} = {\min\left( {{{\hat{P}}_{{PUSCH},k_{UCI},j}(i)},\left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}\; {{\hat{P}}_{{PUCCH},k}(i)}}} \right)} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 14} \right\rbrack \\{{\sum\limits_{k}\; {\sum\limits_{c \neq j}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUSCH},k_{UCI},j}(i)} - {\sum\limits_{k}\; {{\hat{P}}_{{PUCCH},k}(i)}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 15} \right\rbrack\end{matrix}$

Here, {circumflex over (P)}_(PUSCH,k) _(UCI) _(,j)(i) is a linear valueof P_(PUSCH,k) _(UCI) _(,j)(i), and P_(PUSCH,k) _(UCI) _(,j)(i) is aPUSCH transmission power for a serving cell j in a subframe i associatedwith a cell group k where a PUSCH with UCI is transmitted (in thisinstance, the PUSCH for the serving cell j corresponds to a PUSCH withUCI). {circumflex over (P)}_(PUCCH,k)(i) is a linear value ofP_(PUCCH,k)(i), and P_(PUCCH,k)(i) denotes a PUCCH transmission power inthe subframe i for the cell group k. {circumflex over(P)}_(PUSCH,k,c)(i) is a linear value of P_(PUSCH,k,c)(i), andP_(PUSCH,k,c)(i) denotes a PUSCH transmission power for a serving cell cin the subframe i for the cell group k. k denotes an eNB or cell groupindicator. k denotes an eNB (or cell group) indicator indicating an eNBto which (a cell group through which) a PUSCH is transmitted from amongeNBs (MeNB and SeNB) or (cell groups (MCG and SCG)) in dualconnectivity. For example, k=0 indicates a MeNB or a MCG, and k=1indicates a SeNB or a SCG. {circumflex over (P)}_(CMAX)(i) is a linearvalue of a total configured maximum output power P_(CMAX) configured fora UE in a subframe i. w_(k)(i) denotes a scaling factor of {circumflexover (P)}_(PUSCH,k,c)(i) with respect to a serving cell c associatedwith a predetermined eNB or cell group. w_(k)(i) has a value from 0 to 1(0≦w_(k)(i)≦1). w_(k)(i) has an identical value with respect to allserving cells in a single eNB (or a single cell group). That is,w_(k)(i) is an eNB (or cell group)-specific parameter. When a PUCCHtransmission does not exist in a subframe i with respect to acorresponding eNB or cell group, {circumflex over (P)}_(PUCCH,k)(i) maybe 0. For example, when a PUCCH transmission does not exist in thesubframe i with respect to a MCG, {circumflex over(P)}_(PUCCH,k=0)(i)=0, and when a PUCCH transmission does not exist inthe subframe i with respect to a SCG, {circumflex over(P)}_(PUCCH,k=1)(i)=0.

FIG. 12 is a diagram illustrating an example of power scaling withrespect to a PUSCH with UCI and a PUSCH without UCI for Case 2,according to one or more exemplary embodiments. In FIG. 12, CC1 and CC2of an MeNB belongs to an MCG, and CC1 and CC2 of an SeNB belongs to anSCG.

Referring to FIG. 12, a PUSCH with UCI is transmitted in a subframe i onCC1 of an MeNB. Therefore, power scaling using a scaling factor may notbe executed with respect to the PUSCH transmission with UCI in thesubframe i on CC1 of the MeNB. With respect to a PUSCH transmissionwithout UCI in a subframe i on CC2 of the MeNB, power scaling based onw_(k=0)(i) may be executed. With respect to a PUSCH transmission withoutUCI in a subframe i on both CC1 and CC2 of an SeNB, power scaling basedon w_(k=1)(i) may be executed. In this instance, a smaller power scalingmay be executed with respect to the PUSCH transmission without UCI inthe MCG. That is, the PUSCH transmission without UCI in the MCG may havea higher priority than a PUSCH transmission without UCI in the SCG.Alternatively, a smaller power scaling may be executed with respect to aPUSCH transmission without UCI in a cell group having a higher QoS. Thatis, the PUSCH transmission without UCI in the cell group having a higherQoS may have a higher priority than a PUSCH transmission without UCI ina cell group having a lower QoS.

The method basically prioritizes a PUCCH transmission over a PUSCHtransmission, irrespective of a cell group in dual connectivity, andprioritizes a PUSCH transmission with UCI over a PUSCH transmissionwithout UCI. Therefore, the method does not execute power scaling of aPUCCH and a PUSCH with UCI (the power scaling for a PUSCH with UCI willbe described later). However, power scaling based on w_(k)(i) may beexecuted for a PUSCH transmission without UCI.

In this instance, when

${\sum\limits_{k}\; {\sum\limits_{c \neq j}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} = 0$

is not satisfied and a total transmit power of the UE does not exceed{circumflex over (P)}_(CMAX)(i), power scaling may not be applied withrespect to {circumflex over (P)}_(PUSCH,k) _(UCI) _(,j)(i). However,when

${\sum\limits_{k}\; {\sum\limits_{c \neq j}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} = 0$

is satisfied and a total transmit power of the UE still exceeds{circumflex over (P)}_(CMAX)(i), power scaling may need to be appliedwith respect to {circumflex over (P)}_(PUSCH,k) _(UCI) _(,j)(i). Thiswill be described through Method 2 provided below.

(2) Method 2: PUCCH and PUSCH (w/UCI) Power Scaling

Equation 14 does not take into account power scaling with respect to aPUCCH transmission and a PUSCH transmission with UCI. When it is assumedthat the PUCCH transmission and the PUSCH transmission with UCI are alsopower scaled, the UE may obtain {circumflex over (P)}_(PUCCH,k)(i),{circumflex over (P)}_(PUSCH,k) _(UCI) _(,j)(i), and {circumflex over(P)}_(PUSCH,k,c)(i), as shown in equations provided below.

$\begin{matrix}{{\left( {\sum\limits_{k}\; {{g_{k}(i)} \cdot {{\hat{P}}_{{PUCCH},k}(i)}}} \right) + {{h_{k_{UCI}}(i)} \cdot {{\hat{P}}_{{PUSCH},k_{UCI},j}(i)}}} \leq {{\hat{P}}_{CMAX}(i)}} & \left\lbrack {{Equation}\mspace{14mu} 16} \right\rbrack \\{{\sum\limits_{k}\; {\sum\limits_{c \neq j}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - \left( {\sum\limits_{k}\; {{g_{k}(i)} \cdot {{\hat{P}}_{{PUCCH},k}(i)}}} \right) + {{h_{k_{UCI}}(i)} \cdot {{\hat{P}}_{{PUSCH},k_{UCI},j}(i)}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 17} \right\rbrack\end{matrix}$

Here, g_(k)(i) is a scaling factor for {circumflex over(P)}_(PUCCH,k)(i). g_(k)(i) has a value from 0 to 1 (0≦g_(k)(i)≦1). k ing_(k)(i) indicates a predetermined eNB or cell group. That is, gk(i) maybe used for power scaling for a PUCCH transmitted over a predeterminedeNB or cell group. g_(k)(i) values for an MeNB (or MCG) and an SeNB (orSCG) may or may not be identical. Also, h_(k) _(UCI) (i) is a scalingfactor for {circumflex over (P)}_(PUSCH,k) _(UCI) (i). h_(k) _(UCI) (i)has a value from 0 to 1 (0≦h_(k) _(UCI) (i)≦1). Here, k_(UCI) denotes acell group including a cell through which a PUSCH with corresponding UCIis transmitted. When a PUCCH transmission does not exist in a subframe iwith respect to a corresponding eNB or cell group, {circumflex over(P)}_(PUCCH,k)(i) may be 0. For example, when a PUCCH transmission doesnot exist in the subframe i with respect to a MCG, {circumflex over(P)}_(PUCCH,k=0)(i)=0, and when a PUCCH transmission does not exist inthe subframe i with respect to a SCG, {circumflex over(P)}_(PUCCH,k=1)(i)=0.

According to the method, power scaling is executed with respect to aPUSCH transmission without UCI, and power scaling may be independentlyexecuted for each of a PUSCH transmission and a PUSCH transmission withUCI.

FIG. 13 is a diagram illustrating another example of power scaling withrespect to a PUSCH with UCI and a PUSCH without UCI for Case 2,according to one or more exemplary embodiments. In FIG. 13, CC1 and CC2of an MeNB belongs to an MCG, and CC1 and CC2 of an SeNB belongs to anSCG.

Referring to FIG. 13, a PUSCH with UCI is transmitted in a subframe i onCC1 of the MeNB. Therefore, power scaling using a scaling factor h_(k)_(UCI) (i) may be executed with respect to the PUSCH transmission withUCI in the subframe i on CC1 of the MeNB. With respect to a PUSCHtransmission without UCI in a subframe i on CC2 of the MeNB, powerscaling based on w_(k=0)(i) may be executed. With respect to a PUSCHtransmission without UCI in a subframe i on both CC1 and CC2 of theSeNB, power scaling based on w_(k=1)(i) may be executed. In thisinstance, power scaling using g_(k)(i) may be executed with respect to aPUCCH transmission in the subframe I (not illustrated).

Case 3: PUSCH Transmission with UCI Exists in all Cell Groups

(1) Method 1: No PUCCH Power Scaling

When a UE simultaneously transmits a PUCCH and a PUSCH with UCI in aserving cell j and a serving cell l in each cell group (MCG and SCG),transmits a PUSCH without UCI in any of the remaining serving cells, anda total transmit power of the UE exceeds {circumflex over(P)}_(CMAX)(i), the UE may obtain {circumflex over(P)}_(PUSCH,k=0,j)(i), {circumflex over (P)}_(PUSCH,k=1,l)(i), and{circumflex over (P)}_(PUSCH,k,c)(i) as shown in the equations providedbelow.

$\begin{matrix}{{{\hat{P}}_{{PUSCH},{k = 0},j}(i)} = {\min\left( {{{\hat{P}}_{{PUSCH},{k = 0},j}(i)},\left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}\; {{\hat{P}}_{{PUCCH},k}(i)}}} \right)} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 18} \right\rbrack \\{{{\hat{P}}_{{PUSCH},{k = 1},l}(i)} = {\min\left( {{{\hat{P}}_{{PUSCH},{k = 1},l}(i)},\left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUSCH},{k = 0},j}(i)} - {\sum\limits_{k}\; {{\hat{P}}_{{PUCCH},k}(i)}}} \right)} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 19} \right\rbrack \\{{\sum\limits_{k}\; {\sum\limits_{\underset{c \neq l}{c \neq j}}\; {{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUSCH},{k = 0},j}(i)} - {{\hat{P}}_{{PUSCH},{k = 1},l}(i)} - {\sum\limits_{k}\; {{\hat{P}}_{{PUCCH},k}(i)}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 20} \right\rbrack\end{matrix}$

Here, {circumflex over (P)}_(PUSCH,k=0,j)(i) is a linear value ofP_(PUSCH,k=0,j)(i), which is a transmission power with respect to aPUSCH with UCI that is transmitted through the serving cell j of the MCGin the subframe i. {circumflex over (P)}_(PUSCH,k=1,l)(i) is a linearvalue of P_(PUSCH,k=1,l)(i), which is a transmission power with respectto a PUSCH with UCI that is transmitted through the serving cell l ofthe SCG in the subframe i. Although it is described that k=0 correspondsto the MCG, k=1 corresponds to the SCG, the serving cell for the PUSCHtransmission with UCI of the MCG is serving cell j, and the serving cellfor the PUSCH transmission with UCI of the SCG is serving cell l, thismerely an example, which may be differently expressed based on theagreement between a UE and an eNB.

FIG. 14 is a diagram illustrating an example of power scaling withrespect to a PUSCH with UCI and a PUSCH without UCI for Case 3,according to one or more exemplary embodiments. In FIG. 14, CC1 and CC2of an MeNB belongs to an MCG, and CC1 and CC2 of an SeNB belongs to anSCG.

Referring to FIG. 14, a PUSCH with UCI is transmitted in a subframe i onCC1 of the MeNB and a PUSCH with UCI is transmitted in a subframe i onCC1 of the SeNB. Therefore, power scaling using a scaling factor may notbe executed with respect to the PUSCH transmission with UCI in thesubframe i on CC1 of the MeNB and the subframe i on CC1 of the SeNB.Conversely, power scaling based on w_(k=0)(i) and w_(k=1)(i) may beexecuted with respect to a PUSCH transmission without UCI in a subframei on CC2 of the MeNB and a subframe i on CC2 of the SeNB, respectively.In this instance, a smaller power scaling may be executed with respectto a PUSCH transmission without UCI in the MCG or a PUSCH transmissionwithout UCI in a cell group having a higher QoS. That is, the PUSCHtransmission without UCI in the MCG may have a higher priority than aPUSCH transmission without UCI in the SCG. Alternatively, the PUSCHtransmission without UCI in the cell group having a higher QoS may havea higher priority than a PUSCH transmission without UCI in a cell grouphaving a lower QoS.

The method basically prioritizes a PUCCH transmission over a PUSCHtransmission, irrespective of a cell group, and prioritizes a PUSCHtransmission with UCI over a PUSCH transmission without UCI. Therefore,the method does not execute power scaling of a PUCCH and a PUSCH withUCI (the power scaling for a PUSCH with UCI will be described later).However, power scaling based on w_(k)(i) may be executed for a PUSCHtransmission without UCI.

In this instance, when

${\sum\limits_{k}\; {\sum\limits_{\underset{c \neq l}{c \neq j}}{{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} = 0$

is not satisfied and a total transmit power of the UE does not exceed{circumflex over (P)}_(CMAX)(i), power scaling may not be applied withrespect to {circumflex over (P)}_(PUSCH,k=0,j)(i) and {circumflex over(P)}_(PUSCH,k=1,l)(i). However, when

${\sum\limits_{k}\; {\sum\limits_{\underset{c \neq l}{c \neq j}}{{w_{k}(i)} \cdot {{\hat{P}}_{{PUSCH},k,c}(i)}}}} = 0$

is satisfied and a total transmit power of the UE still exceeds{circumflex over (P)}_(CMAX)(i), power scaling may need to be appliedwith respect to {circumflex over (P)}_(PUSCH,k=0,j)(i) and {circumflexover (P)}_(PUSCH,k=1,l)(i). This will be described through Method 2provided below.

(2) Method 2: PUCCH and PUSCH (w/UCI) Power Scaling

Equation 1 does not take into account power scaling for a PUCCHtransmission and a PUSCH transmission with UCI. When it is assumed thatthe PUCCH transmission and the PUSCH transmission with UCI are alsopower scaled, the UE may obtain {circumflex over (P)}_(PUCCH,k)(i),{circumflex over (P)}_(PUSCH,k=0,j)(i), {circumflex over(P)}_(PUSCH,k=1,l)(i), and {circumflex over (P)}_(PUSCH,k,c)(i), asshown in the equations provided below.

$\begin{matrix}{{{\sum\limits_{k}\; {{g_{k}(i)} \cdot {{\hat{P}}_{{PUCCH},k}(i)}}} + \left( {{{h_{k = 0}(i)}{{\hat{P}}_{{PUSCH},{k = 0},j}(i)}} + {{h_{k = 1}(i)}{{\hat{P}}_{{{{PUSCH}.k} = 1},l}(i)}}} \right)} \leq {{\hat{P}}_{CMAX}(i)}} & \left\lbrack {{Equation}\mspace{14mu} 21} \right\rbrack \\{{\sum\limits_{k}\; {\sum\limits_{\underset{c \neq l}{c \neq j}}{{{w_{k}(i)} \cdot {\hat{P}}_{{PUSCH},k,c}}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{k}\; {{g_{k}(i)}{{\hat{P}}_{{PUCCH},k}(i)}}} - {{h_{k = 0}(i)} \cdot {{\hat{P}}_{{PUSCH},{k = 0},j}(i)}} - {{h_{k = 1}(i)} \cdot {{\hat{P}}_{{PUSCH},{k = 1},l}(i)}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 22} \right\rbrack\end{matrix}$

Here, g_(k)(i) is a scaling factor for {circumflex over(P)}_(PUCCH,k)(i). g_(k)(i) has a value from 0 to 1 (0≦g_(k)(i)≦1). k ing_(k)(i) indicates a predetermined eNB or cell group. That is, gk(i) maybe used for power scaling for a PUCCH transmitted over a predeterminedeNB or cell group. g_(k)(i) values for an MeNB (or MCG) and an SeNB (orSCG) may or may not be identical. Also, h_(k)(i) is a scaling factor for{circumflex over (P)}_(PUSCH,k=0,j)(i) and {circumflex over(P)}_(PUSCH,k=1,l)(i). h_(k)(i) has a value from 0 to 1 (0≦h_(k)(i)≦1).k in h_(k)(i) may indicate a predetermined eNB or cell group. When aPUCCH transmission does not exist in a subframe i with respect to acorresponding eNB or cell group, {circumflex over (P)}_(PUCCH,k)(i) maybe 0. For example, when a PUCCH transmission does not exist in thesubframe i with respect to a MCG, {circumflex over(P)}_(PUCCH,k=0)(i)=0, and when a PUCCH transmission does not exist inthe subframe i with respect to a SCG, {circumflex over(P)}_(PUCCH,k=1)(i)=0.

According to the method, power scaling is executed with respect to aPUSCH transmission without UCI, and power scaling may be independentlyexecuted for each of a PUSCH transmission and a PUSCH transmission withUCI. In this instance, power scaling with respect to a PUSCHtransmission with UCI of the MCG and a PUSCH transmission with UCI ofthe SCG, may be independently executed.

FIG. 15 is a diagram illustrating another example of power scaling withrespect to a PUSCH with UCI and a PUSCH without UCI for Case 2,according to one or more exemplary embodiments. In FIG. 15, CC1 and CC2of an MeNB belongs to an MCG, and CC1 and CC2 of an SeNB belongs to anSCG.

Referring to FIG. 15, a PUSCH with UCI is transmitted in a subframe i onCC1 of the MeNB and a subframe i on CC1 of the SeNB, respectively. Inthis instance, power scaling using a scaling factor h_(k=0)(i) may beexecuted with respect to the PUSCH transmission with UCI in the subframei on CC1 of the MeNB and power scaling using a scaling factor h_(k=1)(i)may be executed with respect to the PUSCH transmission with UCI in thesubframe i on CC1 of the SeNB. With respect to a PUSCH transmissionwithout UCI in a subframe i on CC2 of the MeNB, power scaling based onw_(k=0)(i) may be executed. With respect to a PUSCH transmission withoutUCI in a subframe i on CC2 of the SeNB, power scaling based onw_(k=1)(i) may be executed. In this instance, power scaling usingg_(k)(i) may be executed with respect to a PUCCH transmission in thesubframe i.

FIG. 16 is an example of a flowchart illustrating an uplink powercontrolling operation executed by a UE, according to one or moreexemplary embodiments. FIG. 16 assumes that the UE is in dualconnectivity.

Referring to FIG. 16, a UE calculates a total transmit power of the UEin a subframe i for an MCG and an SCG, in operation S1600. In thisinstance, the UE may calculate a transmission power P_(SRS) of an SRS, atransmission power P_(UL) _(_) _(CH) of an uplink channel(s), and atransmission power P_(DMRS) of a Demodulation Reference Signal (DMRS),with respect to the MCG and the SCG. The uplink channel(s) may includeat least one of a PUCCH and a PUSCH. The PUSCH may or may not includeUCI. A UE may calculate a total transmit power of a UE with respect tothe MCG and the SCG, based on a sum of P_(SRS), P_(UL) _(_) _(CH), andP_(DMRS).

The UE determines whether the total transmit power of the UE exceeds{circumflex over (P)}_(CMAX)(i), in operation S1610. Here, {circumflexover (P)}_(CMAX)(i) is a linear value of a total configured maximumoutput power (or a maximum transmit power) P_(CMAX), configured for a UEin a subframe i. When the total transmit power of the UE exceeds{circumflex over (P)}_(CMAX)(i), this may be called as power limitedcase. The power limited case refers to the case where a requiredtransmission power of a UE indicated by an eNB is higher than a maximumtransmission power allowed for the UE while the UE executes uplinktransmission, and the required transmission power is limited.

When the total transmit power of the UE exceeds {circumflex over(P)}_(CMAX)(i) in operation S1610, the UE may execute power control withrespect to at least one of a PUCCH and a PUSCH transmitted in thesubframe i with respect to the MCG and the SCG, in operation S1620.Here, power control may include power scaling. An example of powerscaling is multiplexing an original transmission power by a scalingfactor. In this instance, the UE may apply different power controllingmethods based on the number of cell groups (Case 1, Case 2, or Case 3)that transmit a PUSCH with UCI in a predetermined subframe, as describedin Table 2. Also, the UE may set priorities as shown in Table 3, and mayexecute power controlling (and scaling) based on the priorities. In thisinstance, a scaling factor value may be determined based on a priority.

For example, there is a case (Case 1) in which a cell group thattransmits a PUSCH with UCI in a subframe i, does not exist. In thisinstance, (1) a UE does not execute PUCCH power scaling, and may executepower scaling with respect to {circumflex over (P)}_(PUSCH,k,c)(i) basedon w_(k)(i). In this instance, {circumflex over (P)}_(PUSCH,k,c)(i) maybe scaled based on Equation 4. (2) The UE may execute power scaling withrespect to {circumflex over (P)}_(PUCCH,k)(i) based on g_(k)(i). In thisinstance, {circumflex over (P)}_(PUSCH,k,c)(i) and {circumflex over(P)}_(PUCCH,k)(i) may be scaled based on Equation 5 and Equation 6. (3)The UE may execute power controlling by prioritizing a PUCCHtransmission of a predetermined cell group. In this instance, the UEdoes not use a separate scaling factor g_(k)(i) for a PUCCH, prioritizesa PUCCH transmission corresponding to a predetermined cell group, sets aPUCCH transmission corresponding to the remaining cell group as asubsequent priority, so as to allocate power. In this instance,{circumflex over (P)}_(PUCCH,k)(i) and {circumflex over(P)}_(PUSCH,k,c)(i) may be controlled based on the Equation 7 andEquation 8. (4) When a PUSCH without UCI is transmitted in only a singlecell group (MCG or SCG), the UE may execute power scaling with respectto the PUSCH transmission without UCI. In this instance, {circumflexover (P)}_(PUSCH,k,c)(i) may be scaled based on Equation 9. (5) When aPUSCH without UCI is transmitted in only a single cell group (MCG orSCG), the UE may execute power scaling with respect to a PUCCHtransmission, in addition to power scaling with respect to the PUSCHtransmission without UCI. In this instance, {circumflex over(P)}_(PUCCH,k)(i) and {circumflex over (P)}_(PUSCH,k,c)(i) may be scaledbased on Equation 10 and Equation 11. (6) When a PUSCH without UCI istransmitted in only a single cell group (MCG or SCG), the UE may executepower controlling by prioritizing a PUCCH transmission of apredetermined cell group. In this instance, {circumflex over(P)}_(PUCCH,k)(i) and {circumflex over (P)}_(PUSCH,k,c)(i) may becontrolled based on the Equation 12 and Equation 13.

As another example, there is a case (Case 2) in which only a single cellgroup that transmits a PUSCH with UCI in a subframe i, exists. In thisinstance, (1) a UE does not execute PUCCH power scaling, and may executepower scaling with respect to {circumflex over (P)}_(PUSCH,k,c)(i) basedon w_(k)(i). In this instance, {circumflex over (P)}_(PUSCH,k) _(UCI)_(,j)(i) and {circumflex over (P)}_(PUSCH,k,c)(i) may be scaled based onEquation 14 and Equation 15. (2) The UE may execute power scaling withrespect to a PUCCH and a PUSCH with UCI. In this instance, {circumflexover (P)}_(PUCCH,k)(i), {circumflex over (P)}_(PUSCH) _(UCI) _(,j)(i),and {circumflex over (P)}_(PUSCH,k,c)(i) may be scaled based on Equation16 and Equation 17.

As another example, there is a case (Case 3) in which both the MCG andthe SCG are cell groups that transmit a PUSCH with UCI in a subframe i.In this instance, (1) the UE does not execute PUCCH power scaling, andmay execute power controlling with respect to {circumflex over(P)}_(PUSCH,k=0,j)(i), {circumflex over (P)}_(PUSCH,k=1,l)(i), and{circumflex over (P)}_(PUSCH,k,c)(i), based on Equations 18 to 20. (2)The UE may execute power scaling with respect to a PUCCH and a PUSCHwith UCI. In this instance, {circumflex over (P)}_(PUCCH,k)(i),{circumflex over (P)}_(PUSCH,k=0,j)(i), {circumflex over(P)}_(PUSCH,k=1,l)(i), and {circumflex over (P)}_(PUSCH,k,c)(i) may bescaled based on Equation 21 and Equation 22.

Subsequently, the UE may execute uplink transmission in a subframe iwith respect to the MCG and the SCG, based on the power controlling, inoperation S1630.

When the total transmit power of the UE does not exceed {circumflex over(P)}_(CMAX)(i) in operation S1610, the UE may execute uplinktransmission in the subframe i with respect to the MCG and the SCG,without power controlling, in operation S1640.

FIG. 17 is an example of a block diagram illustrating a UE, according toone or more exemplary embodiments.

Referring to FIG. 17, a UE 1700 includes a receiving unit 1705, a UEprocessor 1710, and a transmitting unit 1720. The UE processor 1710 mayinclude a calculator 1711 and a power controller 1712.

The receiving unit 1705 may receive a downlink signal from an eNB (notillustrated). The downlink signal may include dual connectivityconfiguration information. In addition, the downlink signal may includeuplink scheduling information for the UE.

The calculator 1711 calculates a total transmit power of the UE in asubframe i for an MCG and an SCG. In this instance, the calculator 1711may calculate a transmission power P_(SRS) of an SRS, a transmissionpower P_(UL) _(_) _(CH) of an uplink channel(s), and a transmissionpower P_(DMRS) of a Demodulation Reference Signal (DMRS), with respectto the MCG and the SCG. The uplink channel(s) may include at least oneof a PUCCH and a PUSCH. The PUSCH may or may not include UCI. Thecalculator 1711 may calculate a total transmit power of the UE withrespect to the MCG and the SCG, based on a sum of P_(SRS), P_(UL) _(_)_(CH), and P_(DMRS).

The power controller 1712 determines whether the calculated totaltransmit power of the UE exceeds {circumflex over (P)}_(CMAX)(i).{circumflex over (P)}_(CMAX)(i) is a linear value of a total configuredmaximum output power (or a maximum transmission power) P_(CMAX),configured for the UE in the subframe i. The power controller 1712 mayexecute power controlling with respect to at least one of a PUCCH and aPUSCH transmitted in the subframe i when the calculated total transmitpower of the UE exceeds {circumflex over (P)}_(CMAX)(i). Here, powercontrol may include power scaling. An example of power scaling ismultiplexing an original transmission power by a scaling factor. In thisinstance, the power controller 1712 may apply different powercontrolling methods based on the number of cell groups (Case 1, Case 2,or Case 3) that transmit a PUSCH with UCI in a predetermined subframe,as described in Table 2. The power controller 1712 may set priorities asshown in Table 3, and may execute power controlling (and scaling) basedon the priorities. In this instance, a scaling factor value may bedetermined based on a priority.

The transmitting unit 1720 may execute uplink transmission in thesubframe i with respect to the MCG and the SCG, based on the powercontrolling. In this instance, based on the dual connectivity configuredfor the UE, the transmitting unit 1720 may execute uplink transmissionto a MeNB through an MCG, and simultaneously, may execute uplinktransmission to an SeNB through the SCG.

According to one or more exemplary embodiments, a UE may control atransmit power of an uplink channel. The UE may be capable ofconfiguring dual connectivity and the transmit power may be controlledwhen the UE maintains dual connectivity with an MeNB and at least oneSeNB.

The UE may establish an RRC connection with a MeNB through a primaryserving cell, and the MeNB may be associated with an MCG including oneor more serving cells configurable for the UE. The UE may establish aconnection with an SeNB, and the SeNB may be associated with an SCGincluding one or more serving cells configurable for the UE.

The UE may determine to transmit an uplink channel through a servingcell of the MCG and to transmit an uplink channel through a serving cellof the SCG. The UE may determine a priority between the uplink channeldetermined to be transmitted through the serving cell of the MCG and theuplink channel determined to be transmitted through the serving cell ofthe SCG, based on Uplink Control Information (UCI) included in at leastone of the uplink channels and based on a type of a cell group.

The UE may control the transmit power reduction for a lower-prioritizeduplink channel from among the uplink channels, and transmit the uplinkchannels through the respective serving cells after the control of thetransmit power reduction.

Further, the UE may receive an RRC message through the primary servingcell. The RRC message may include carrier aggregation (CA) configurationinformation, and the CA configuration information may includeinformation of one or more secondary serving cells to be aggregatedaccording to a CA configuration. The one or more serving cells may beincluded in at least one of the MCG and the SCG.

The uplink channel determined to be transmitted through the serving cellof the MCG and the uplink channel determined to be transmitted throughserving cell of the SCG may be configured to be transmitted in subframei. The UE may determine to reduce a transmit power of at least oneuplink channel in response to a determination that the total transmitpower exceeds the output power threshold in the subframe i. The outputpower threshold in the subframe i may correspond to {circumflex over(P)}_(CMAX)(i) defined above.

The priority may be determined primarily based on the UCI and determinedsecondarily based on the type of a cell group. Here, the type of a cellgroup may include the MCG and the SCG. An uplink channel transmittedthrough the MCG may have a higher priority than an uplink channeltransmitted through the SCG if the lower-prioritized uplink channel isnot determined based on the UCI.

If a first uplink channel is determined to be transmitted through aserving cell of the SCG without including UCI and a second uplinkchannel is determined to be transmitted through a serving cell of theMCG without including UCI, the first uplink channel may be determined tohave a lower priority than the second uplink channel by setting apriority for the MCG higher than a priority for the SCG.

If the uplink channels have a same priority based on a UCI criterion,the uplink channel determined to be transmitted through the serving cellof the SCG may be determined to have a lower priority than the uplinkchannel determined to be transmitted through the serving cell of theMCG. Further, if the uplink channel determined to be transmitted throughthe serving cell of the SCG includes UCI and the uplink channeldetermined to be transmitted through the serving cell of the MCG doesnot include UCI, the uplink channel determined to be transmitted throughthe serving cell of the MCG may be determined to have a lower prioritythan the uplink channel determined to be transmitted through the servingcell of the SCG. The uplink channels may include at least one of aPhysical Uplink Control Channel (PUCCH) and a Physical Uplink SharedChannel (PUSCH).

The UE may determine that an uplink channel including a SchedulingRequest (SR) or a Hybrid Automatic Repeat Request Acknowledgement(HARQ-ACK) has a higher priority than an uplink channel includingChannel State Information (CSI). The controlling the transmit powerreduction for the lower-prioritized uplink channel may include scaling atransmit power for the lower-prioritized uplink channel. If a PUCCH anda PUSCH to be transmitted in subframe i are determined to have the samepriority based on a UCI criterion, the PUCCH may be determined to have ahigher priority than the PUSCH.

According to one or more exemplary embodiments, a UE may maintain dualconnectivity by connecting to an MeNB and an SeNB. The UE may determineto transmit an uplink channel through a first serving cell of the SCGand to transmit an uplink channel through a second serving cell of theSCG. The UE may determine whether to control a transmit power reductionfor at least one of the uplink channel determined to be transmittedthrough the first serving cell of the SCG and the uplink channeldetermined to be transmitted through the second serving cell of the SCG.The UE may determine a priority between the uplink channel determined tobe transmitted through the serving cell of the MCG and the uplinkchannel determined to be transmitted through the serving cell of theSCG, based on a determination whether Uplink Control Information (UCI)is included in at least one of the uplink channels and a determinationof a UCI characteristic. The UE may control the transmit power reductionfor a lower-prioritized uplink channel from among the uplink channels,and transmit the uplink channels through the respective serving cellsafter the control of the transmit power reduction.

According to one or more exemplary embodiments, the priority may bedetermined based on the number of cell groups that transmit a PUSCH withUCI from among a Master Cell Group (MCG) and a Secondary Cell Group(SCG). In this instance, PUSCH/PUCCH transmission power controlling maybe effectively executed with respect to the UE for which dualconnectivity is configured, and the performance of uplink scheduling maybe improved.

The above description is to explain exemplary embodiments of inventiveconcept, and it will be apparent to those skills in the art thatmodifications and variations can be made without departing from thespirit and scope of inventive concept. Thus, it is intended that thepresent invention cover the modifications and variations of exemplaryembodiments provided they come within the scope of the appended claimsand their equivalents.

What is claimed is:
 1. A method of controlling transmit power of anuplink channel to be transmitted from a User Equipment (UE), the UEbeing capable of configuring dual connectivity, the method comprising:establishing, by a Master evolved NodeB (MeNB), a Radio Resource Control(RRC) connection with the UE through a primary serving cell, the MeNBbeing associated with a Master Cell Group (MCG) including one or moreserving cells configurable for the UE; establishing, by a Secondary eNB(SeNB), a connection with the UE, the SeNB being associated with aSecondary Cell Group (SCG) including one or more serving cellsconfigurable for the UE; transmitting, by the MeNB to the UE, an RRCmessage through the primary serving cell, the RRC message comprisingcarrier aggregation (CA) configuration information, and the CAconfiguration information comprising information of one or moresecondary serving cells to be aggregated according to a CAconfiguration, and the one or more serving cells being included in atleast one of the MCG and the SCG; determining an uplink channel to bereceived from the UE through a serving cell of the MCG in subframe i,and determining an uplink channel to be received from the UE through aserving cell of the SCG in the subframe i; determining an output powerthreshold in the subframe i, which is associated with a transmit powerreduction for at least one of the uplink channel determined to bereceived through the serving cell of the MCG and the uplink channeldetermined to be received through the serving cell of the SCG in thesubframe i; and receiving the uplink channel from the UE through theserving cell of the MCG in subframe i, and receiving the uplink channelfrom the UE through the serving cell of the SCG in subframe i.
 2. Themethod of claim 1, wherein a priority between the uplink channeldetermined to be received through the serving cell of the MCG and theuplink channel determined to be received through the serving cell of theSCG is based on Uplink Control Information (UCI) included in at leastone of the uplink channels and based on a type of a cell group, andwherein the transmit power reduction is applied for a lower-prioritizeduplink channel from among the uplink channels.
 3. The method of claim 1,further comprising: when total transmit power for uplink transmissionsfrom the UE in the subframe i exceeds the output power threshold in thesubframe i, receiving at least one uplink channel from the UE in thesubframe i with reduced transmit power.
 4. The method of claim 3,wherein the output power threshold in the subframe i corresponds to{circumflex over (P)}_(CMAX)(i), a linear value of a total configuredmaximum output power P_(CMAX) configured for the UE in the subframe i.5. The method of claim 2, wherein an uplink channel transmitted throughthe MCG has a higher priority than an uplink channel transmitted throughthe SCG if the lower-prioritized uplink channel is not determined basedon the UCI.
 6. The method of claim 1, wherein the uplink channels eachcomprise at least one of a Physical Uplink Control Channel (PUCCH) and aPhysical Uplink Shared Channel (PUSCH).
 7. The method of claim 2,wherein an uplink channel including a Scheduling Request (SR) or aHybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) has a higherpriority than an uplink channel including Channel State Information(CSI).